eugene h. buder anne s. warlaumont d. kimbrough oller

NOVA Comprehensive Perspectives on Child Speech Development and Disorders

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Chapter 4

An Acoustic Phonetic Catalog of Prespeech Vocalizations from a Developmental Perspective

Eugene H. BuderAnne S. WarlaumontD. Kimbrough Oller


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Introduction• Protophones (volitional prespeech vocalizations) can be

considered precursors to speech– Only humans produce them– Developmental sequence– Increasingly resemble speech– Disruptions are seen in children with disorders

• This chapter– Presents a glossary of protophones with details on how to code

them– Comments on order of occurrence– Presents spectrograms and sound files with notes on audible and

acoustic features


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• “Discontinuity theory” (Jakobson, 1941 in German, 1968 in English translation): Babble is random and unrelated to speech development later on

• Evidence to the contrary: Babble is closely related to early speech development (Stoel-Gammon & Cooper, 1984)– The characteristics of sounds in the late babble stages

resemble the segments and syllable structures of first words– For a while (approximately ages 11 to 20 months), infants

produce both babble and words

History of the Protophone Approach to Studying Infant Vocalizations


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History of the Protophone Approach, cont.

• Prior to the late 1970’s, pre-speech vocalizations were either– Transcribed phonetically using the same phonetic categories as those used for adults, or– Focused on acoustic features using the same parameters as those used for adults

• New approach: “Protophones” (Koopmans-van Beinum & van der Stelt, 1986; Oller, 1980, Stark, 1980)

• Protophones are– More primitive productions that are different from the sounds catalogued in the International

Phonetic Alphabet– Precursors of speech sound development– Reflexive, non-volitional sounds such as cries, laughs, and burps, are not protophones

• The stages of protophone development appear to be independent of the child’s ambient language

• Research on protophones– Hearing impairment, autism (Paul et al., 2011; Sheinkopf et al., 2000)– Infant/caregiver dyads (Warlaumont et al., 2010; Buder et al., 2010)– Social reinforcement (Goldstein & Schwade, 2008)– Automatic classification (Warlaumont et al., 2010)


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Guidelines for Coding Protophone Categories

• Exclude fixed signals (e.g., crying, laughter) and sounds of physiologic origin (e.g., sneezing)

• Code at the utterance level– Breath groups can be used to determine utterance boundaries

• Forced-choice protocol may be used for certain features– E.g., use the most salient feature for phonation qualities for squeal vs.

growl, even if the utterance has elements of two or more– Allow combinations of phonatory and articulatory features, e.g., a

canonical babble can also be a squeal• Focus on general categories (often overlooking narrow ‘phonetic’

details)– Take guidance from caregivers, who regularly interpret and group infant’s

vocalization as possible signals to be acted on


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Glossary of Protophone Categories

• Reflexive– Cries, fusses– Laughs– Vegetative sounds

• Protophone– Phonation related– Syllabification/articulation related


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Phonation Related Protophones

• Quasivowel (vocant: articulatory tract in neutral position)

• Full vowel (vocant: adjusted articulatory tract)• Squeal: high pitch• Growl: harsh vocal quality or low pitch (often fry)• Whisper: no phonation• Yell: loud• Ingressive vocalization• Ingressive-egressive sequence


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Articulation and Syllabification Related Protophones

• Raspberry: trill or vibrant• Click: release of negative pressure• Goo: closure usually back of tract, erratic timing• Glottal sequence: vocants with glottal stop interrupts• Marginal babble: closant plus vocant but imprecise

timing• Canonical babble: syllabic timing– Reduplicated: repetition of an identical syllable [dada]– Variegated: string of non-identical syllables [mani]


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Comments on Order of Development and Ages of Onset in Protophones

• Numerous publications have addressed stages of protophone development• Similar findings across studies (Oller, 2000)

– Crying and vegetative sounds are present at birth but laughter emerges around age 4 months

– The earliest protophones including quasivowels and glottal stop sequences occur right after birth

– Gooing occurs at 1 to 4 months, usually in interaction with caregivers– By 3 months, many new protophones appear (full vowels, raspberries, squeals,

growls, yells, whispers, marginal babble)– Canonical babbles appear in the second half of the first year

• Whether reduplicated babble always precedes variegated babble is not clear– Onset of canonical babble past age 10 months is grounds for clinical concern; seen

in children with profound hearing impairment, often in Down syndrome, and Williams syndrome


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An Acoustic Phonetic Catalog of Examples of Selected Protophones

4S1 through 4S20: Protophone Examples 1 through 20

Note: These samples were selected to provide guidance with subtle characteristics of protophones. Excluded are non-protophones and protophones with obvious perceptual and acoustic characteristics (whispers, clicks, extensive examples of canonical babble) and those categories with less clearly defined characteristics (variegated babble, gibberish)

Editors also provided 4S21: Cry of a one-week-old infant, and4S22: Recording of a 9-week-old infant, to support Suggested Activities


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Example 1. A quasivowel, produced by an infant aged 3 ½ months. Quasivowels are produced with a neutral (resting) vocal tract configuration and are typically quiet and short.

F1


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Example 2. Another quasivowel, produced by the same infant at the same age (3½ months) as Example 1.


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Example 3. A goo, preceded by a quasivowel, and followed by a full vowel, produced by the same infant at the same age as preceding examples.


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We categorized Example 4 on the left as a quasivowel, and Example 5 on the right as a full vowel. These examples are displayed here side by side to reinforce some additional principles and distinguishing characteristics regarding quasivowels and full vowels as isolated types of vocalizations (i.e., as nucleus-only vocalizations lacking syllabic margins). While Example 5 has been coded as a full vowel, rather than a quasivowel, it is not the most unambiguous of cases. Examples 4 and 5 were produced by a much older infant, aged approximately 11 months, which reinforces the fact that early-emerging protophones may still occur even though infants this age will normally also be producing fully articulated canonical syllables.


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Example 6 returns to the younger infant from previous examples (aged 3½ months), and illustrates a more complex sequence that includes some previous types, including goo and full vowel, and introduces a new protophone type, the raspberry.


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Examples 7 and 8 are presented here side by side to compare varieties of raspberry. The raspberries presented in examples 6-8 were produced by the same 3 ½ month old child during one 20 minute recording session. One possible interpretation of this phenomenon is that the infant was exploring her ability to produce sounds by controlling pressures and airflows with a valving mechanism other than at the glottis (i.e., the lips). Depending on the speed of labial vibration a raspberry may be a trill, a vibrant with salient roughness (as in Example 6), or even a very high frequency vibrant that produces a tonal characteristic, like the lip action using in playing a trumpet.


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Example 9 introduces a glottal sequence. This vocalization is one of many produced in a single 20 minute session by an infant nearly 4 months of age, who seemed to be practicing with the glottal valving operation. Because the beginning of the utterance includes a presumably velar closure, the utterance would best be characterized within the forced choice system as a goo (the most advanced protophone category to which the utterance pertains), but here we illustrate that it also has the characteristics of a glottal stop sequence.


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Example 10 is a growl, produced by a different child but also at about 4 months of age.


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Examples 11 and 12 above are two more examples of growls and help illustrate that the term encompasses quite a range of possible variations from normal phonation. The growl on the left was produced by an older infant at about 10 months of age, and the growl on the right by a different infant at about 4 months of age.


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Example 13 is a squeal, produced by the same 4-monther who produced the growl of Example 12 (and recorded in the same session). Vertical lines on the bottom plot are at 1 kHz intervals.


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Example 14 is another squeal, produced by the same infant in Example 13, but at 6 months.


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Example 15 is a yell, produced by a 10 month old infant.


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Examples 16 on the left is a marginal babble produced by a 12 month old girl, and Example 17 on the right is a canonical babble produced by the same infant in the same recording session.


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Example 18 on the left is another marginal babble produced by a 10 month old girl, and Example 19 on the right is a canonical babble produced by the same child in the same recording session.


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Example 20 is a single breath group sequence of reduplicated canonical syllables, a kind of celebration of babbling that adult listeners recognize as truly speech-like and to which they are usually therefore tempted to ascribe meaning. The infant producing this example was 10 ½ months old.


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Connections

• Chapter 3: biological substrates• The current chapter: pre-speech vocalizations• Chapter 5: from pre-speech to first words• Chapter 19: pre-speech development in

infants with hearing impairment and developmental disabilities


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Concluding Remarks• This chapter discusses the categorization of pre-speech

vocalizations into protophones – Historical perspectives– Theoretical perspectives– Practical guidelines on how to apply protophone categorization– Protophone development– Increasing similarities to speech

• Timing• Articulation • Complexity

– Audible and Spectrographic features

eugene h. buder anne s. warlaumont d. kimbrough oller

Documents

child speech development

prespeech vocalizations

protophone approach

phonetic categories

late babble stages

canonical babble

characteristics of sounds

nonvolitional sounds