dekeyser 2005 language learning

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What Makes Learning Second-LanguageGrammar Difficult? A Review of Issues

Robert M. DeKeyserUniversity of Pittsburgh

If the ability to use language in the restricted sense (i.e., a

communication system characterized by double articulation) is

quintessentially human, then explaining this ability is a crucial

task for cognitive science, and explaining its acquisition is a

crucial task for developmental psychology. If the difficulty of

acquiring a second language (L2), at least at a later age, stands

in sharp contrast to the child’s celebrated accomplishments, thenexplaining this contrast is equally important for developing a

complete understanding of humans’ abilities to use and acquire

language. In fact, it can be argued that it is the enormous

contrast between the two phenomena that needs explaining,

rather than either of the two phenomena per se. One way to

tackle this problem is the social science approach of correlating

age and many other demographic variables with success in

acquisition: to disentangle design features of the species fromaccidental characteristics of the environment. Another approach

consists of investigating what elements or characteristics of an

L2 are hard to acquire: to understand better how weaknesses in

the acquisition process interact with the design features of human

languages. And of course, one can look at the two variables in

interaction with each other: Which problematic elements of the

Correspondence concerning this article should be addressed to Robert

DeKeyser, Department of Linguistics, University of Pittsburgh, Pittsburgh

PA 15260, USA. Internet: [email protected]

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language are an issue in L2 learning at any age, and which

are mostly a problem for later acquirers only? Or even better,

how do five different variables interact in L2 acquisition: the

characteristics of the L2, the influence of the first language (L1),

the role of age, the role of individual differences in cognitive and

affective ‘‘aptitudes,’’ and the role of learning context, be it the

native-speaking environment or the classroom, the latter

representing, of course, a wide variety of learning contexts

with different degrees of emphasis on form and meaning?

The focus of this introductory review article is on the char-

acteristics of the L2 itself (and its differences from L1) that make

its acquisition difficult. Given the very broad nature of the topic,

I will touch on the issues of age, other individual differences, and

learning context only to the extent that they cannot be ignored

because nothing can be generalized without taking them into

account. I also restrict discussion to morphosyntax rather than

phonology or the lexicon and to the acquisition of competence

rather than processing, recognizing here too that all suchseparations are to some extent superficial because the meaning

of morphemes and the distribution of their allomorphs cannot be

acquired without the phonological capacity to extricate them from

the flood of sounds in every sentence, and because competence is

only a (some would say fictional) abstraction of what humans do

when they understand or produce language, and acquiring this

competence necessarily happens through processing input

(cf., esp., Pienemann, 2003; Truscott & Sharwood Smith, 2004).Finally, I emphasize publications from the past 5 years in keeping

with the criteria for selecting articles for the Best of Language

Learning series.

Broad Definitions of Difficulty

Even a cursory glance at some well-known discussions of what

is difficult in L2 acquisition shows how tricky this concept is.

Krashen (1982) and R. Ellis (1990), for instance, at first sight

appear to agree that one needs to make a distinction between

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formal and functional complexity. But the same structure, third

person –s in English as a Second Language (ESL), was classified

by Krashen (1982) as easy to learn because it is simple, and by

Ellis (1990) as hard to learn because it is complex. One might

think that the reason for this discrepancy is that Krashen was

dealing with learning in the narrow sense here (as opposed to

implicit acquisition) and Ellis with a broader meaning of learning,

but when one looks at their reasons for classifying this structure

as easy or difficult, it is clear that they used different criteria for

deciding on the complexity of –s: Krashen pointed to the simple

dichotomous choice between supplying this simple morpheme or

not, whereas Ellis, referring to Pienemann (1984), pointed to the

long-distance relationship between the grammatical number of

the subject and the presence or absence of –s on the verb. Nor is the

disagreement due to a mere focus on formal complexity by Krashen

versus a broader look at the form-function relationship by Ellis:

The latter actually goes beyond Krashen by considering even the

form-function relationship for –s to be simple (‘‘transparent’’); it isonly because of the processing operations required that Ellis

considered the structure to be complex (1990, p. 167).

It appears, then, that at least three factors are involved

in determining grammatical difficulty: complexity of form,

complexity of meaning, and complexity of the form-meaning

relationship. Even this picture, however, is not complete; it

actually leaves out the core psycholinguistic difficulty of

acquisition, that is, the difficulty of grasping the form-meaningrelationship while processing a sentence in the L2. Rather than

forms, meanings, or form-meaning relationships, it is the trans-

parency of form-meaning relationships to a learner who is

processing language for meaning that determines the difficulty

of acquisition, at least for learners who are left to their own

resources instead of presented with a reasonably complete set

of rules about form-meaning relationships.

Part of what determines this transparency is the degree of

importance of a linguistic form for the meaning it expresses:

Certain morphemes are the one and only clue to the meaning

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they express; others are largely or completely redundant, because

they mark grammatical agreement with meanings whose primary

representations are elsewhere in the sentence or the discourse.

VanPatten (e.g., 1990) has therefore emphasized the distinction

between meaningful and redundant for predicting what will be

easy or hard to acquire, especially in early stages of L2 development.

Some researchers—most notably Stockwell, Bowen, and

Martin (1965)—have drawn up elaborate hierarchies of difficulty

of acquisition based on form-meaning mapping. But the work of

Stockwell, Bowen, and Martin (1965) focused primarily on

Spanish, put more emphasis on L1–L2 surface differences than

is warranted by more recent research on the role of L1, and was

largely nonempirical. They also left out completely the notion of

salience in the input, presumably because they were thinking of

instructed learning contexts, in which salience is less of an issue

than in naturalistic L2 acquisition, a phenomenon that was not

yet a topic of research at that time.

Other researchers, recognizing the difficulty of definingdifficulty, have avoided a theoretical conceptualization altogether.

When structures needed to be classified according to difficulty,

they chose to ask teachers to rate L2 structures for the level of

difficulty they seemed to present intuitively (e.g., Robinson, 1996).

While such an approach may be a useful operationalization,

depending on the nature of the study, it still leaves us with the

question of what constitutes difficulty.

In what follows, I present various components of grammaticaldifficulty, with at least a modest amount of empirical evidence for

their importance in acquisition or lack thereof and for how they fit

into the broader picture of interaction with each other and with

individual and contextual factors (the latter including L1 as well

as instruction). One way of isolating components of difficulty is to

look separately at problems of meaning, problems of form, and

problems of form-meaning mapping.



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Problems of Meaning

Regardless of the form used to express a meaning, the meaningitself can constitute a source of difficulty, because of novelty,

abstractness, or a combination of both. Articles, classifiers,

grammatical gender, and verbal aspect are notoriously hard to

acquire for native speakers of L1s that do not have them or that

use a very different system (for articles in ESL, see, e.g., Jarvis,

2002; Liu & Gleason, 2002; Robertson, 2000; Tarone & Parrish,

1988; Thomas, 1989; Young, 1996; cf. also Celce-Murcia & Larsen-

Freeman, 1999, chap. 15; for classifiers in Japanese and Chinese,

see, e.g., Hansen & Chen, 2001; for grammatical gender in a

variety of languages, see, e.g., Carroll, this volume; Kempe &

Brooks, this volume; Taraban, 2004; Williams & Lovatt, this

volume; for aspect in Romance or Germanic languages, see, e.g.,

Andersen & Shirai, 1994, 1996; Bardovi-Harlig, 1998, 1999, 2000;

Collins, 2002; Dietrich, Klein, & Noyau, 1995; Lee, 2001; Montrul

& Slabakova, 2003; Salaberry, 2000).These elements of grammar are even strongly resistant to

instructional treatments (for aspect see, e.g., Ayoun, 2004; Ishida,

2004; for gender see, e.g., Leeman, 2003; for articles see, e.g.,

Butler, 2002; Master, 1997). What they all have in common is

that they express highly abstract notions that are extremely hard

to infer, implicitly or explicitly, from the input. Where the

semantic system of the L1 is different from that of the L2, as is

very often the case for aspect, or where equivalent notions do notget expressed overtly in L1, except through discourse patterns, as

may be the case for ESL articles for native speakers of most Slavic

languages or Chinese, Japanese, or Korean, the learning problem

is serious and long-lasting.

Problems of Form

Difficulty of language form is largely an issue of complexity.

Assuming the learner knows exactly the meanings that need to be

expressed, difficulty of form could be described as the number of

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choices involved in picking all the right morphemes and

allomorphs to express these meanings and putting them in the

right place. Clearly, this problem is most complex in richly

inflected languages, whether they be agglutinative, polysynthetic,

or inflectional in the narrow sense. Everything else (such as

semantic difficulty) being the same, the more that needs to be

expressed overtly, the more choices need to be made about

morphemes, allomorphs, and their position. Morphology in L2 is

hard: Basic word order is typically nonproblematic past the initial

stages of acquisition, but even the most basic morphology is often

lacking from the speech of untutored immigrants (see, e.g., Klein

& Dittmar, 1979) and of classroom learners who are not able to

monitor themselves effectively (see, e.g., Krashen & Pon, 1975;

Tarone, 1985). Morphology is even shakily represented in

learners’ intuitions, even after many years of exposure to the L2

(e.g., DeKeyser, 2000; Johnson & Newport, 1989).

Much ink has been spent discussing whether continuing

failure to supply these morphemes systematically is truly aproblem of competence or one of ‘‘mere performance.’’ Given the

poor scores of adult immigrants on grammaticality judgment tests

on this point (in ESL, e.g., third person –s, articles, or plurals in

DeKeyser, 2000; Johnson & Newport, 1989; Yeni-Komshian,

Robbins, & Flege, 2001) and the failure of intermediate English-

speaking foreign language students even to take into account the

meaning of elementary morphology in order to come to the correct

understanding of a sentence (see, esp., VanPatten, 2004; cf. alsoMacWhinney, 2001, in press), it seems safe to conclude that more

than processing is at stake. Jiang (2004), in particular, showed

convincingly that errors of verb agreement with complex noun

phrases in ESL were due to lack of sensitivity to plural marking

on the noun, not to problems with processing agreement.

This problem of L2 users’ failing to use morphology, even in

comprehension, is so fundamental that it has by itself spawned

entire bodies of literature. The research on processing instruction

has showed that students benefit from intensive training in paying

attention to elements of morphology for comprehension, because



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without such practice they tend to gloss over the morphology

(especially students of a morphology-poor language like English

acquiring a relatively morphology-rich language like Spanish).

The interpretation of various aspects of the processing-instruction

literature has been controversial (see, e.g., DeKeyser, Salaberry,

Robinson, & Harrington, 2002; VanPatten & Wong, 2002). But

nobody doubts that L2 students need to have their attention

drawn to morphology while processing input, because otherwise

they tend to ignore the morphological cues to sentence meaning.

The research within the framework of the competition model,

on the other hand, has shown repeatedly, with speakers of a

variety of L1s and L2s, that morphology is a weak cue in initial

stages of language learning, at least for English L1 speakers, and

that if it becomes stronger over time, this only happens in a very

slow and gradual fashion (cf., esp., MacWhinney, 2001, in press;

see, e.g., Hertel, 2003; Kempe & MacWhinney, 1998; McDonald,

1987).

More formal approaches to morphosyntax, however differentthey may be in other respects, coincide in singling out morphology

as hard to acquire in comparison with syntax. Lardiere (1998),

Prévost and White (2000), and Sprouse (1998) provide evidence

that morphological and syntactic features that are closely linked

in syntactic theory (verb raising and inflection) are not acquired

together. One way out of this problem, from the point of view of a

theory in which such a link is seen as crucial, is the view that

learners acquire the syntactic features easily but continue to haveproblems with their morphological instantiation (cf. Sorace, 2003,

and Lardiere’s summary of several of her own articles in Long,

2003).

Problems of Form-Meaning Mapping

Even assuming that neither form nor meaning is particularly

problematic according to the criteria mentioned in the previous

two sections, acquiring the form-meaning mapping can still be

difficult if the link between form and meaning is not transparent.

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Such lack of transparency can be due to at least three factors:

redundancy, optionality, or opacity.

Redundancy means that the form at issue is not semanti-

cally necessary because its meaning is also expressed by at least

one other element of the sentence; for example, a verb ending

can be redundant because the subject is explicit, whether it be a

full noun phrase or a pronoun, which makes person and number

information redundant, and because adverbs or other lexical

items make information such as tense or aspect redundant

(cf., e.g., VanPatten, 1990). When the redundant element is also

abstract and novel, then the learning problem is particularly

severe: Robinson (2002), for instance, showed that learners of

Samoan L2 had more trouble with the ergative marker than

with the locative or noun incorporation, because the ergative

marker (both novel for learners of L1 English and abstract) was

semantically redundant, which the other two structures were not.

Optionality of certain elements, such as null subjects in

Spanish or Italian (see, e.g., Herschensohn, 2000; Liceras, 1989)or case marking in Korean, only makes matters worse. Not only

does the optional character of the case marking or the overt

subject pronoun suggest it is redundant, but its alternating

presence or absence in the presence of the same meaning,

except for subtle aspects of pragmatics, makes the form-

meaning link even harder to establish. (This optionality in the

L2 as a cause of acquisition problems is not to be confused with

‘‘optionality’’ in the sense of interlanguage variability, which is aconsequence of a variety of problems with the acquisition of

features that are not variable in the L2; cf. Papp, 2000; Prévost

& White, 2000; Robertson, 2000; Sorace, 2000, 2003.)

Opacity is a complex form of the problem of low form-meaning

correlation. When a morpheme has different allomorphs, and at

the same time it is homophonous with other grammatical

morphemes, then the correlation between form and meaning

becomes very hard to detect: Different forms stand for the same

meaning, and the same form stands for different meanings. This,

of course, is exactly the case for –s in English, which can be the



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third-person singular of the verb, the plural of the noun, or the

genitive of the noun and in each case has the same three

allomorphs. Where third-person singular is concerned, this

problem of low correlation between form and meaning is further

compounded by the so-called morpheme’s really being a morph (a

chunk of sound isolated in morphological analysis, but without a

one-to-one mapping with any meaning), in this case conflating

three different meanings (singular, third person, present tense),

all of which are expressed by separate morphemes in many

languages, and all of which have to be present at the same time

for –s to appear, and all of which are rather abstract and therefore

difficult by themselves. More generally, instances of morphological

irregularity, such as irregular plurals and irregular past tenses, all

fall into this category: The problem is not so much a problem of

form (an irregular is not necessarily more formally complex); it is

the form-meaning mapping that becomes more opaque and/or

complex.

Other examples of opaque form-meaning mappings can befound in syntax, such as the relationship between the order of

subject and verb in Spanish, on the one hand, and the lexical

semantics of the verb and the discourse functions of subject-verb

inversion, on the other hand. Hertel (2003) showed how learners

of L2 Spanish do not use much verb-subject (VS) order till they

are quite advanced in their L2 proficiency and that even

the advanced learners do not make any distinction between

unergatives and unaccusatives when it comes to VS order, eventhough native speakers clearly do. The optional nature of the VS

order makes it even harder to acquire its correlation with the

abstract semantic elements that favor its appearance. DeKeyser

(2005) also documents a virtual total absence of VS order for

any kind of verb in declarative sentences among intermediate

Spanish learners during a 6-week stay in Argentina. Jung’s

(2004) finding that English speakers did not acquire topic

prominence in Korean L2 till the advanced level, in spite of the

hypothetical universal nature of topic prominence in early inter-

language, can be seen as another example of how difficult it is to

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map a variable phenomenon to abstract discourse-dependent

semantics. To the learner, many cases of opacity probably appear

to be instances of optionality.

The acquisition problem is compounded even further when

optionality and discourse-motivated preferences for one of the

options interact with arbitrary or semantically obscure subcat-

egorization restrictions, such as, in Japanese L2, the restriction of

goal PPs to directed-motion verbs (Inagaki, 2001) or the restriction

of quantifier floating to unaccusatives (Sorace & Shomura, 2001),

and in English L2, the restriction of agentive use to manner-of-

motion verbs as opposed to change-of-state verbs (Montrul, 2001),

the restrictions on dative alternation (see esp. Inagaki, 1997;

Whong-Barr & Schwartz, 2002), and those on locative alternation

(see esp. Bley-Vroman & Joo, 2001; Joo, 2003; Juffs, 1996). The

possibility of alternation seems to be motivated by semantic

criteria, but according to Pinker (1989), at least 14 semantically

defined verb classes need to be distinguished for locative

alternation and 10 for dative alternation. When, on top of that,relevant input is very limited in ESL materials (Juffs, 1998) and

probably even in more natural input, it is clear that acquisition is

a challenge, to say the least. Even simpler subcategorization

restrictions, such as which English verbs take an infinitive and

which a gerund, appear to be problematic, even after decades of

exposure to the language (DeKeyser, 2000; Flege, Yeni-Komshian,

& Liu, 1999; Johnson & Newport, 1989; McDonald, 2000).

Finally, an important factor that helps determine ease ordifficulty of learning form-meaning mappings is, of course,

frequency. N. Ellis (2002, 2003) provided evidence from a variety

of sources on the role of frequency in L2 learning. He argued that

the typical route of acquisition of grammar structures is from

formulae through low-scope patterns to constructions and that

the abstraction of regularities within these constructions is

frequency-based. In principle, the importance of frequency is

independent of semantic transparency, but how important

frequency is depends to some extent on the transparency of the

mapping. If the mapping is very clear, minimal exposure may be



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enough for acquisition; if it is very obscure, the structure may well

never be acquired by adults. If the transparency of the mapping is

in between these two extremes, frequency may largely determine

whether the mapping is acquired or not, in further interaction, of

course, with the learner’s aptitude and (methods of) instruction.

Hansen and Chen (2001), for instance, provided a clear example of

a set of morphemes in which frequency played a very important

role: classifiers in Chinese and Japanese L2. As the structure is

fairly salient and its function is clear, but the choice of the right

form is based on semantic criteria that are hard to define, the level

of difficulty is such that the role of frequency is maximized.

Where to Look for Direct Evidence on What Is Difficult?

I have presented a number of factors that make the

acquisition of L2 grammar difficult, attempting to organize

evidence from a wide variety of studies which addressed all

kinds of narrowly focused questions about the acquisition of grammar, but in the process I have also documented aspects

of the difficulty of specific language structures. Relatively few

studies have actually attempted a systematic empirical investi-

gation of difficulty by comparing acquisition for a broad range of

language structures. The vast majority of studies either have a

narrow linguistic focus or a very wide linguistic scope with little

or no interest in comparing acquisition of different structures

systematically. In principle, there are several research areas inwhich one could look for systematic evidence—documentation of

fossilization, ultimate attainment studies with adult learners, and

research on order of acquisition—but not all of these areas have

yielded much that can help answer the question of what makes an

L2 structure difficult.

Fossilization is a concept that has been around for decades,

but the concept has remained rather vague. If one uses a narrow

definition, such as that of Long (2003), requiring that learners

have been fully exposed to the L2 for at least 10 years and that

lack of change for a specific structure has been systematically

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documented for at least 5 years, then it turns out that only

a handful of studies have met this criterion. Long (2003) cited

Han (2000), Lardiere (1998, 2000), and Long (1997), which have

documented fossilization of, respectively, nontarget unaccusa-

tive verbs, missing verb morphology, and lexically determined

inflection on nouns and verbs.

Ultimate attainment studies of adult learners—with the goal

of establishing age effects—have become popular in the last decade

or so, but again not many have engaged in a systematic comparison

of how well different aspects of grammar have been acquired. The

only studies in the morphosyntax category that have explored

differential age effects for different language elements are

Birdsong (1992), DeKeyser (2000), DeKeyser, Ravid, and Alfi-

Shabtay (2005), Flege et al. (1999), Johnson and Newport (1989,

1991), and McDonald (2000).

Both Birdsong (1992) and Johnson and Newport (1989, 1991)

made a distinction between structures within and outside of the

realm of universal grammar. Birdsong made a direct comparisonwithin his study and found that both categories of structures were

equally sensitive to age effects. Johnson and Newport carried out

two studies, one with structures outside of Universal Grammar

(UG; 1989), the other with structures exemplifying the subjacency

principle, assumed to be an element of UG (1991). They found

essentially the same strong age effect in both studies. It should be

pointed out, however, that the UG/non-UG classification in

Birdsong (1992) was tentative, as the author indicated himself,and that the classification of subjacency among the principles of

UG is not uncontroversial either (Huang, 1982; Pesetsky, 1987;

Rizzi, 1982).

Flege et al. (1999) made a different kind of distinction. They

administered an ESL grammaticality judgment test, mostly

drawn from Johnson and Newport (1989), to speakers of Korean

L1 and found overall age-proficiency correlations of .71 for age

on arrival (AoA)15. The researchers

showed, through analysis of a series of subsamples matched for

AoA, that education was a significant predictor for performance



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on rule-based items and use of English was a significant predictor

for performance on lexically based items.

Johnson and Newport (1989), DeKeyser (2000), and McDonald

(2000), all using variants of the same grammaticality judgment test

for English L2, found a tendency for a few elements of morphosyn-

tax to be resistant to age effects, especially basic word order and

yes/no questions. Moreover, both Flege et al. (1999) and McDonald

(2000) found that auxiliaries, subcategorization and wh-questions

were more sensitive to length of residence or other measures of

usage than AoA. On the basis of such patterns and further post

hoc analyses of his own data (for instance, successful acquisition of

subject-verb inversion in yes-no questions, but not in wh-questions),

DeKeyser (2000) hypothesized a strong role of salience, in the sense

that this variable becomes increasingly important with age.

One more study to mention here is Yeni-Komshian et al.

(2001). Among the Korean speakers of L2 English in this study,

performance was markedly worse for plural –s than for third-person

–s, and this difference became gradually larger with increasing AoA.The authors of this study attributed the difference in correctness

between noun phrase (NP) and verb phrase (VP) to the higher

salience of the VP in Korean L1 and to a transfer of processing

strategies in this respect.

In contrast to ultimate attainment studies, research on

acquisition order, of course, has made explaining difficulty into

an explicit goal, at least if one accepts that difficulty can be

operationalized as order of acquisition. This type of researchwas prominent from the early 1970s to the early 1980s, but while

researchers eventually agreed on a more or less universal order of

acquisition of grammatical morphemes in ESL, they could not

agree on an explanation for that order (cf., e.g., Gass & Selinker,

2001; Larsen-Freeman & Long, 1991; Long & Sato, 1984). This

lack of explanatory adequacy was probably one of the main reasons

why the order-of-acquisition question for morphemes faded from

the published literature in the mid-1980s. Parallel work on

acquisition order of syntactic patterns such as interrogative

structures (e.g., Eckman, Moravcsik, & Wirth, 1989) or relative

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clauses (e.g., Eckman, Bell, & Nelson, 1988; Gass, 1979), however,

pointed to markedness as a potentially important factor in

determining order of acquisition/difficulty. Bardovi-Harlig (1987),

on the other hand, showed that salience prevailed over

markedness by comparing the acquisition of pied piping and

preposition stranding in ESL. Goldschneider and DeKeyser (this

volume) returned to the issue of morpheme acquisition order and

found that salience—broadly construed as a combination of phono-

logical salience, semantic complexity, morphological regularity, and

frequency—accounted for a large percentage of the variance in the

order of L2 acquisition. They found it impossible to tease out the

contribution of the various components of salience, however,

because these factors are strongly intercorrelated in English

morphology.

Given the evidence for the importance of salience in both the

ultimate-attainment and the order-of-acquisition literatures, on

the one hand, and the lack of systematic research on the role of

salience in ultimate attainment by adult learners, on the otherhand, DeKeyser, Ravid, and Alfi-Shabtay (2005) decided to

investigate the role of salience in the acquisition of Hebrew

morphology by adult immigrants. They found not only a strong

effect of salience in determining difficulty (as measured by

a grammaticality judgment test), but also a significant interaction

with age in the sense that the role of salience grew more important

with increasing age of acquisition. Further analysis of the data

(DeKeyser, Alfi-Shabtay, Ravid, & Shi, 2005) showed that severalcomponents of salience played an independent role in determining

difficulty for all learners: phonological salience (length in phones

and þ / syllabic character of the morpheme) and þ / homonymy

with other morphemes. Two other components of salience did

not show a main effect but interacted with age in the sense

that they were an important predictor of learning for older

learners only: distance (between morphemes in agreement

patterns) and stress.

In conclusion, there is increasing evidence from both the

order-of-acquisition literature and the ultimate-attainment



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literature that lack of salience plays an important role in

acquisition difficulty. Much remains to be done in this area,

however. On the one hand, it is much harder to agree on an

operationalizaton of salience in syntax as opposed to morphology

or phonology. On the other hand, even for morphology, there is still

a lack of systematic, let alone cross-linguistic, research comparing

acquisition difficulty for morphemes with different degrees of

salience or different degrees of other factors mentioned above, for

that matter, such as redundancy, optionality, and opacity of form-

meaning mapping, novelty and abstractness of meaning, and sheer

complexity of form. As research on ultimate attainment effects is

accumulating, there is hope, however, that a meta-analysis of that

literature may soon be able to help determine the characteristics of

consistently poorly learned L2 structures.

Mitigating Factors

Meanwhile, additional insights on what is difficult and whycome from studies that have investigated the interaction

between characteristics of the L2 structures being learned and

individual learner or contextual factors. While a substantial

literature exists on individual differences, not much work has

addressed the question of the differential impact of factors such

as aptitude and motivation on specific elements within

morphology and syntax, in other words, on elements char-

acterized by specific types of difficulty. Two recent studies thatstand out in this area, however, are Willliams (1999) and

Williams and Lovatt (this volume).

The findings of both studies are complex, but Williams (1999)

showed that meaningful form-function mapping (in Italian L2)

resulted from conceptually driven, explicit learning (a function of

aptitude in the sense of grammatical sensitivity), whereas seman-

tically redundant agreement rules were largely the result of data-

driven, implicit learning (a function of memory). DeKeyser (2003)

argued that this is because the agreement rules amounted to

concrete sound-sound correspondences (even euphony), whereas

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the meaningful form-function mappings required associating an

element of the noun phrase with an element of the verb phrase,

each element taking a very different concrete form. Associating

nonmeaningful co-occurrence of concrete elements logically draws

more on memory, whereas establishing meaningful relationships

between abstract entities draws more on insight (cf. Gomez, 1997;

Perruchet & Pacteau, 1990, 1991; Reed & Johnson, 1998). Williams

and Lovatt (this volume) found that even for more abstract

patterns of morpheme agreement, not involving euphony, phono-

logical short-term memory played an important role; there was also

evidence, however, that explicit processes were strongly involved in

learning these patterns.

It is interesting to compare these findings to those of

Taraban (2004), who studied induction of gender-like categories

in miniature linguistic systems. He did not take individual

difference measures but found that learning was greatly

facilitated either by providing explicit instruction or by drawing

learners’ attention to the correlated sets of grammaticalmorphemes by means of blocking trials as a function of noun

category. When time is limited and the pattern is made salient,

explicit learning (presumably drawing on aptitude) is clearly

important; when there is more time and when the pattern is far

less salient, as would be the case in naturalistic language

acquisition, the role of more implicit learning, relying more

heavily on mere associative memory, is likely to increase.

Few researchers so far seem to have ventured further andinvestigated how linguistic characteristics of the patterns to

be acquired interact with both individual differences and

instructional conditions at the same time. Robinson (2002), for

instance, provided interesting data on the interaction between

aptitudes, on the one hand, and linguistic characteristics of the

structures to be learned, instructional conditions, or testing

conditions, on the other hand, but not on the three-way

interaction between linguistic characteristics, instructional

conditions, and aptitudes. Robinson (1996), on the other hand,

documented an interaction between linguistic characteristics



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and instructional conditions (i.e., instructed learners outperformed

others in learning simple rules), but he did not investigate an

interaction with aptitude. Robinson (1997), however, did

document a three-way interaction between structure, aptitude,

and instructional condition, in the sense that the learning of easy

structures was predicted by grammatical sensitivity but not by

memory and the learning of complex structures by memory but

not by grammatical sensitivity, for instance, and that this pattern

only obtained for one of the four instructional conditions (‘‘rule

search,’’ i.e., inductive explicit learning).

Implications for Instruction

The nature and degree of difficulty of individual structures

have a range of potential implications for instructional decision

making. At the most basic level, one can argue that instruction is

not necessary for the easiest structures and doomed to failure for

the hardest, in particular where focus on form is concerned(cf. DeKeyser, 2003). Within form-focused instruction, however,

whether it be characterized by traditional focus on forms or more

narrowly defined focus on form (cf. Long & Robinson, 1998),

different activities are likely to have a differential impact on

different structures characterized by different learning

problems. Larsen-Freeman (2003, pp. 117–120), for instance,

made distinctions among three kinds of activities, aimed at

association (e.g., through phrase combination tasks), frequentuse, and choice (e.g., in a fill-in-the blanks format). She

associated these three kinds of activities with the problems of

learning the meaning of a grammar structure, the form itself, or

its use, respectively. Within the terminological framework I have

used in the present article, one could argue that association

activities are particularly useful when the learning issue is one

of form-meaning mapping, that frequent use should be the goal

when the problem is one of semantically redundant form-form

mapping, and that choice among forms should be the focus of the

activity when novel meanings are at issue.

DeKeyser 17


18/25

Much empirical work needs to be done in order to test

hypotheses such as these, but they should provide a useful

starting point for research that goes beyond the simplistic

question of whether explicit grammar teaching and systematic

practice are useful for L2 grammar learning.

The Articles in This Volume

The four articles that follow were all published in Language

Learning between 1999 and 2003. They are all about the

acquisition of L2 morphology. Three are about the acquisition

of gender in particular: Kempe and Brooks demonstrate how

diminutives facilitate gender acquisition in Russian L2 by

eliminating nontransparent morphophonological marking. Carroll

shows that gender acquisition in French L2 is largely

determined by the semantic distinctions the learner makes on

the basis of previous linguistic experience. Williams and Lovatt

document the role of individual differences, in particular,

phonological short-term memory, in the acquisition of gender

in a semiartificial miniature linguistic system.

These three studies illustrate with different methodologies

and with different languages how factors such as consistency of

form-meaning mapping, semantically driven insights derived

from prior linguistic knowledge, and the learner’s phonological

short-term memory all play an important role in solving adifficult problem in acquisition: form-meaning mapping, in which

the form is complex and the meaning redundant, abstract, and

novel. Together with Goldschneider and DeKeyser’s meta-analysis

of a wider range of morphological elements, these studies show

how success in L2 acquisition is strongly influenced by (a) how

transparent the form-meaning link is to the learner, either

because of the salience of the linguistic structure itself or

because its apperception is facilitated by the structure or thefrequency of the input, or (b) the learner’s aptitudes and

previous linguistic experience.



19/25

References

Andersen, R. W., & Shirai, Y. (1994). Discourse motivations for some

cognitive acquisition principles. Studies in Second Language Acquisition,

16, 133–156.

Andersen, R. W., & Shirai, Y. (1996). The primacy of aspect in first and second

language acquisition: The pidgin-creole connection. In W. C. Ritchie &

T. K. Bhatia (Eds.), Handbook of second language acquisition (pp.

527–570). San Diego, CA: Academic Press.

Ayoun, D. (2004). The effectiveness of written recasts in the second

language acquisition of aspectual distinctions in French: A follow-up

study. Modern Language Journal, 88, 31–55.

Bardovi-Harlig, K. (1987). Markedness and salience in second-language

acquisition. Language Learning, 37 , 385–407.

Bardovi-Harlig, K. (1998). Narrative structure and lexical aspect: Conspiring

factors in second language acquisition of tense-aspect morphology.

Studies in Second Language Acquisition, 20, 471–508.

Bardovi-Harlig, K. (1999). From morpheme studies to temporal semantics:

Tense-aspect research in SLA. Studies in Second Language Acquisition,

21, 341–382.

Bardovi-Harlig, K. (2000). Tense and aspect in second language acquisition:

Form, meaning, and use. Malden, MA: Blackwell.

Bley-Vroman, R., & Joo, H.-R. (2001). The acquisition and interpretation of

English locative constructions by native speakers of Korean. Studies in

Second Language Acquisition, 23, 207–219.

Birdsong, D. (1992). Ultimate attainment in second language acquisition.

Language, 68, 706–755.

Butler, Y. G. (2002). Second language learners’ theories on the use of

English articles: An analysis of the metalinguistic knowledge used by

Japanese students in acquiring the English article system. Studies in


Celce-Murcia, M., & Larsen-Freeman, D. (1999). The grammar book: An

ESL/EFL teacher’s course. Boston: Heinle & Heinle.

Collins, L. (2002). The roles of L1 influence and lexical aspect in the

acquisition of temporal morphology. Language Learning, 52, 43–94.

DeKeyser, R. M. (2000). The robustness of critical period effects in second

language acquisition. Studies in Second Language Acquisition, 22, 499–533.

DeKeyser, R. M. (2003). Implicit and explicit learning. In C. Doughty &

M. Long (Eds.), Handbook of second language acquisition (pp. 313–348).

Oxford, UK: Blackwell.

DeKeyser 19


20/25

DeKeyser, R. M. (2005). Monitoring processes in Spanish as a second

language during a study abroad program. Manuscript in preparation.

DeKeyser, R. M., Alfi-Shabtay, I., Ravid, D., & Shi, M. (2005). The role of salience in the acquisition of Hebrew as a second language. Manuscript

in preparation.

DeKeyser, R. M., Ravid, D., & Alfi-Shabtay, I. (2005). Cross-linguistic

evidence for the nature of age effects in second language acquisition.

Manuscript in preparation.

DeKeyser, R. M., Salaberry, R., Robinson, P., & Harrington, M. (2002). What

gets processed in processing instruction? A commentary on Bill VanPatten’s

‘‘Processing Instruction: An Update.’’ Language Learning, 52, 805–823.

Dietrich, R., Klein, W., & Noyau, C. (1995). The acquisition of temporalityin a second language. Amsterdam: Benjamins.

Eckman, F. R., Bell, L., & Nelson, D. (1988). On the generalization of relative

clause instruction in the acquisition of English as a second language.

Applied Linguistics, 9, 1–20.

Eckman, F. R., Moravcsik, E. A., & Wirth, J. R. (1989). Implicational

universals and interrogative structures in the interlanguage of ESL

learners. Language Learning, 39, 173–205.

Ellis, N. (2002). Frequency effects in language processing: A review with

implications for theories of implicit and explicit language acquisition. Studies in Second Language Acquisition, 24, 143–188.

Ellis, N. (2003). Constructions, chunking, and connectionism: The emergence of

second language structure. In C. J. Doughty & M. H. Long (Eds.), Handbook

of second language acquisition (pp. 63–103). Oxford, UK: Blackwell.

Ellis, R. (1990). Instructed second language acquisition. Oxford, UK:

Blackwell.

Flege, J. E., Yeni-Komshian, G. H., & Liu, S. (1999). Age constraints on second-

language acquisition. Journal of Memory and Language, 41, 78–104.

Gass, S. M. (1979). Language transfer and universal grammatical relations. Language Learning, 29, 327–344.

Gass, S. M., & Selinker, L. (2001). Second language acquisition. An intro-

ductory course. Mahwah, NJ: Erlbaum.

Gómez, R. L. (1997). Transfer and complexity in artificial grammar learning.

Cognitive Psychology, 33, 154–207.

Han, Z. (2000). Persistence of the implicit influence of NL: The case of the

pseudo-passive. Applied Linguistics, 21(1), 55–82.

Hansen, L., & Chen, Y. L. (2001). What counts in the acquisition and

attribution of numeral classifiers? JALT Journal, 23, 90–110.Herschensohn, J. (2000). The second time around: Minimalism and L2

acquisition. Amsterdam: Benjamins.



21/25

Hertel, T. J. (2003). Lexical and discourse factors in the second language

acquisition of Spanish word order. Second Language Research, 19, 273–304.

Huang, C.-T. (1982). Logical relations in Chinese and the theory of grammar. Unpublished doctoral dissertation, Massachusetts Institute

of Technology, Cambridge, MA.

Inagaki, S. (1997). Japanese and Chinese learners’ acquisition of the

narrow-range rules for the dative alternation in English. Language

Learning, 47 , 637–669.

Inagaki, S. (2001). Motion verbs with goal PPs in the L2 acquisition of English

and Japanese. Studies in Second Language Acquisition, 23, 153–170.

Ishida, M. (2004). Effects of recasts on the acquisition of the aspectual form

-te i-(ru) by learners of Japanese as a foreign language. Language Learning, 54, 311–394.

Jarvis, S. (2002). Topic continuity in L2 English article use. Studies in


Jiang, N. (2004). Morphological insensitivity in second language processing.

Applied Psycholinguistics, 25, 603–634.

Johnson, J. S., & Newport, E. L. (1989). Critical period effects in second

language learning: The influence of maturational state on the acquisition

of English as a second language. Cognitive Psychology, 20, 60–99.

Johnson, J. S., & Newport, E. L. (1991). Critical period effects on universalproperties of language: The status of subjacency in the acquisition of a

second language. Cognition, 39, 215–258.

Joo, H.-R. (2003). Second language learnability and the acquisition of

English locative verbs by Korean speakers. Second Language Research,

19, 305–328.

Juffs, A. (1996). Semantics-syntax correspondences in second language

acquisition. Second Language Research, 12, 177–221.

Juffs, A. (1998). The acquisition of semantics-syntax correspondences and verb

frequencies in EL materials. Language Teaching Research, 2, 93–123.Jung, E. H. (2004). Topic and subject prominence in interlanguage

development. Language Learning, 54, 713–738.

Kempe, V., & MacWhinney, B. (1998). The acquisition of case marking by

adult learners of Russian and German. Studies in Second Language

Acquisition, 20, 543–587.

Klein, W., & Dittmar, N. (1979). Developing grammars. Berlin: Springer.

Krashen, S. D. (1982). Principles and practice in second language

acquisition. Englewood Cliffs, NJ: Prentice-Hall.

Krashen, S. D., & Pon, P. (1975). An error analysis of and advanced ESLlearner. Working Papers in Bilingualism, 7 , 125–129.

DeKeyser 21


22/25

Lardiere, D. (1998). Case and tense in the ‘‘fossilized’’ steady-state. Second

Language Research, 14, 1–26.

Lardiere, D. (2000). Mapping features to forms in second languageacquisition. In J. Archibald (Ed.), Second language acquisition and

linguistic theory (pp. 102–129). Oxford, UK: Blackwell.

Larsen-Freeman, D. (2003). Teaching language: From grammar to

grammaring. Boston: Heinle.

Larsen-Freeman, D., & Long, M. H. (1991). An introduction to second

language acquisition research. New York: Longman.

Lee, E.-J. (2001). Interlanguage development by two Korean speakers of

English with a focus on temporality. Language Learning, 51, 591–633.

Leeman, J. (2003). Recasts and second language development: Beyondnegative evidence. Studies in Second Language Acquisition, 25, 37–63.

Liceras, J. M. (1989). On some properties of the ‘‘pro-drop’’ parameter: Looking

for missing subjects in nonnative Spanish. In S. Gass & J. Schachter (Eds.),

Linguistic perspectives on second language acquisition (pp. 109–133). New

York: Cambridge University Press.

Liu, D., & Gleason, J. L. (2002). Acquisition of the article the by nonnative

speakers of English: An analysis of four nongeneric uses. Studies in


Long, M. H. (1997). Fossilization: Rigor mortis in living linguistic systems?Plenary address to the EUROSLA 97 conference, Universitat Pompeu

Fabra, Barcelona, Spain.

Long, M. H. (2003). Stabilization and fossilization in interlanguage

development. In C. J. Doughty & M. H. Long (Eds.), Handbook of second

language acquisition (pp. 487–535). Oxford, UK: Blackwell.

Long, M. H., & Robinson, P. (1998). Focus on form: Theory, research, and

practice. In C. Doughty & J. Williams (Eds.), Focus on form in classroom

second language acquisition (pp. 15–41). New York: Cambridge University

Press.Long, M. H., & Sato, C. (1984). Methodological issues in interlanguage

studies: An interactionist perspective. In A. Davies, C. Criper, & A. P. R.

Howatt (Eds.), Interlanguage (pp. 253–279). Edinburgh, UK: Edinburgh

University Press.

MacWhinney, B. (2001). The competition model: The input, the context, and

the brain. In P. Robinson (Ed.), Cognition and second language instruction

(pp. 69–90). New York: Cambridge University Press.

MacWhinney, B. (in press). A unified model of language acquisition. In

J. F. Kroll & A. M. B. de Groot (Eds.), Handbook of bilingualism: Psycho-linguistic approaches. Oxford, UK: Oxford University Press.



23/25

Master, P. (1997). The English article system: Acquisition, function, and

pedagogy. System, 25, 215–232.

McDonald, J. L. (1987). Sentence interpretation in bilingual speakers of English and Dutch. Applied Psycholinguistics, 8, 379–414.

McDonald, J. L. (2000). Grammaticality judgments in a second language:

Influences of age of acquisition and native language. Applied Psycholin-

guistics, 21, 395–423.

Montrul, S. (2001). Agentive verbs of manner of motion in Spanish and

English as second languages. Studies in Second Language Acquisition,

23, 171–206.

Montrul, S., & Slabakova, R. (2003). Competence similarities between native

and near-native speakers: An investigation of the preterite-imperfectcontrast in Spanish. Studies in Second Language Acquisition, 25, 351–398.

Papp, S. (2000). Stable and developmental optionality in native and non-native

Hungarian grammars. Second Language Research, 16, 173–200.

Perruchet, P., & Pacteau, C. (1990). Synthetic grammar learning: Implicit rule

abstraction or explicit fragmentary knowledge? Journal of Experimental

Psychology: General, 119, 264–275.

Perruchet, P., & Pacteau, C. (1991). Implicit acquisition of abstract knowledge

about artificial grammar: Some methodological and conceptual issues.

Journal of Experimental Psychology: General, 120, 112–116.Pesetsky, D. (1987). Wh-in-situ: Movement and unselective binding. In

E. Reuland & A. G. B. ter Meulen (Eds.), The representation of indefinite-

ness (pp. 98–129). Cambridge, MA: MIT Press.

Pienemann, M. (1984). Psychological constraints on the teachability of

languages. Studies in Second Language Acquisition, 6, 186–214.

Pienemann, M. (2003). Language processing capacity. In C. J. Doughty & M.

H. Long (Eds.), Handbook of second language acquisition (pp. 679–714).

Oxford, UK: Blackwell.

Pinker, S. (1989). Learnability and cognition: The acquisition of argumentstructure. Cambridge, MA: MIT Press.

Prévost, P., & White, L. (2000). Missing surface inflection or impairment in

second language acquisition? Evidence from tense and agreement. Second


Reed, J. M., & Johnson, P. J. (1998). Implicit learning: Methodological issues and

evidence of unique characteristics. In M. A. Stadler & P. A. Frensch (Eds.),

Handbook of implicit learning (pp. 261–294). Thousand Oaks, CA: Sage.

Rizzi, L. (1982). Issues in Italian syntax. Dordrecht, The Netherlands: Foris.

Robertson, D. (2000). Variability in the use of the English article system byChinese learners of English. Second Language Research, 16, 135–172.

DeKeyser 23


24/25

Robinson, P. (1996). Learning simple and complex second language rules

under implicit, incidental, rule-search, and instructed conditions.

Studies in Second Language Acquisition, 18, 27–67.Robinson, P. (1997). Individual differences and the fundamental similarity

of implicit and explicit adult second language learning. Language

Learning, 47 (1), 45–99.

Robinson, P. (2002). Effects of individual differences in intelligence,

aptitude, and working memory on adult incidental SLA: A replication

and extension of Reber, Walkenfield, and Hernstadt (1991). In

P. Robinson (Ed.), Individual differences and instructed language

learning (pp. 211–265). Amsterdam/Philadelphia: Benjamins.

Salaberry, R. (2000). The development of past tense morphology in L2 Spanish. Philadelphia: Benjamins.

Sorace, A. (2000). Syntactic optionality in non-native grammars. Second


Sorace, A. (2003). Near-nativeness. In C. J. Doughty & M. H. Long (Eds.),

Handbook of second language acquisition (pp. 130–151). Oxford, UK:

Blackwell.

Sorace, A., & Shomura, Y. (2001). Lexical constraints on the acquisition of

split intransitivity: Evidence from L2 Japanese. Studies in Second

Language Acquisition, 23, 247–278.Sprouse, R. (1998). Some notes on the relationship between inflectional

morphology and parameter setting in first and second language

acquisition. In M. Beck (Ed.), Morphology and its interfaces in second

language knowledge (pp. 41–67). Amsterdam: Benjamins.

Stockwell, R. P., Bowen, J. D., & Martin, J. W. (1965). The grammatical

structures of English and Spanish. Chicago: University of Chicago Press.

Taraban, R. (2004). Drawing learners’ attention to syntactic context aids gender-

like category induction. Journal of Memory and Language, 51, 202–216.

Tarone, E. E. (1985). Variability in interlanguage use: A study of style-shiftingin morphology and syntax. Language Learning, 35, 373–404.

Tarone, E. E., & Parrish, B. (1988). Task-related variation in interlan-

guage: The case of articles. Language Learning, 38, 21–44.

Thomas, M. (1989). The acquisition of English articles by first- and second-

language learners. Applied Psycholinguistics, 10, 335–355.

Truscott, J., & Sharwood Smith, M. (2004). Acquisition by processing: A

modular perspective on language development. Bilingualism: Language

and Cognition, 7 , 1–20.

VanPatten, B. (1990). Attending to form and content in the input: Anexperiment in consciousness. Studies in Second Language Acquisition,

12, 287–301.



25/25

VanPatten, B. (2002a). Processing instruction: An update. Language Learning,

52, 755–803.

VanPatten, B. (2002b). Processing the content of input-processing andprocessing instruction research: A response to DeKeyser, Salaberry,

Robinson, and Harrington. Language Learning, 52, 825–831.

VanPatten, B. (2004). Input processing in second language acquisition. In

B. VanPatten (Ed.), Processing instruction: Theory, research, and

commentary (pp. 5–31). Mahwah, NJ: Erlbaum.

Whong-Barr, M., & Schwartz, B. D. (2002). Morphological and syntactic

transfer in child L2 acquisition of the English dative alternation. Studies

in Second Language Acquisition, 24, 579–616.

Williams, J. N. (1999). Memory, attention, and inductive learning. Studiesin Second Language Acquisition, 21, 1–48.

Wong, W. (2001). Modality and attention to meaning and form in the input.

Studies in Second Language Acquisition, 23, 345–368.

Yeni-Komshian, G., Robbins, M., & Flege, J. E. (2001). Effects of word class

differences on L2 pronunciation accuracy. Applied Psycholinguistics, 22,

283–299.

Young, R. (1996). Form-function relationships in articles in English inter-

language. In R. Bayley & D. Preston (Eds.), Second language acquisition

and linguistic variation (pp. 135–175). Amsterdam: Benjamins.

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