language technology: research and development topic: verbal …nivre/master/intro_vmwe.pdf ·...

Language Technology:Research and Development

Topic: Verbal Multiword Expressions

Fabienne Cap

Aug. 31th, 2016

What is this bear doing?

The red bear marches to a di↵erent drummer.Der rote Bar tanzt aus der Reihe. (= dances out of the order)L’ours rouge nage a contre-courant. (= swims against the stream)El oso rojo sale de la fila. (= step out of the line)

But:Where is the drummer?Is it really dancing?... or swimming?Is it a line it was standing in?

Fabienne Cap Language Technology:Research and DevelopmentTopic: Verbal Multiword Expressions

The red bear marches to a di↵erent drummer.

Der rote Bar tanzt aus der Reihe. (= dances out of the order)L’ours rouge nage a contre-courant. (= swims against the stream)El oso rojo sale de la fila. (= step out of the line)

The red bear marches to a di↵erent drummer.Der rote Bar tanzt aus der Reihe. (= dances out of the order)

L’ours rouge nage a contre-courant. (= swims against the stream)El oso rojo sale de la fila. (= step out of the line)

The red bear marches to a di↵erent drummer.Der rote Bar tanzt aus der Reihe. (= dances out of the order)L’ours rouge nage a contre-courant. (= swims against the stream)

El oso rojo sale de la fila. (= step out of the line)

But:Where is the drummer?

Is it really dancing?... or swimming?Is it a line it was standing in?

But:Where is the drummer?Is it really dancing?

... or swimming?Is it a line it was standing in?

But:Where is the drummer?Is it really dancing?... or swimming?

Is it a line it was standing in?

Verbal Multiword Expressions

Such expressions are called verbal multiword expressions(VMWEs).

They form a unit that crosses word boundaries (whitespaces).

Just like the bear, VMWEs march to a di↵erent drummer

they behave unlike literal expressions of the same kind.Consider for example their meaning:

to kick the bucket ! to die (VMWE)to kick the ball ! to kick the ball (literal combination)

Definitions

Selected definitions from the literature:

Multiword Expressions (MWEs) are idiosyncraticinterpretations that cross word boundaries. (Sag et al. 2002)

A Multiword Expression is usually taken to be any wordcombination (adjacent or otherwise) that has some feature(syntactic, semantic or purely statistic) that cannot bepredicted on the basis of its component words and/or thecombinatorial process of language. (Bannard, 2007)

... there are many more definitions and terms used to describethe phenomenon, e.g. Idioms, Fixed Expressions,Collocations.

For here and now, we stick with verbal MWEs

Definitions

“Special” at di↵erent levels

MWEs are special at one or more levels of linguistic description:

non-compositional semantics:let the cat out of the bag(VMWE) 6=fixed syntax:to go bananas (VMWE) vs. *bananas are gone

fixed morphology:

feed to the lions (VMWE) vs. Litfeed to the lion

frequency: combination occurs more frequently than expectedvaguely remember (VMWE) vs. *vaguely recall

fixed morphology:

Identification of VMWEs

Their special behaviour can be used to identify them!

feature identificationnon-compositional semantics word alignmentfixed syntax count occurring variantsfixed morphology count occurring variantsfequency statistical association measures

feature identification

non-compositional semantics word alignmentfixed syntax count occurring variantsfixed morphology count occurring variantsfequency statistical association measures

feature identificationnon-compositional semantics word alignment

fixed syntax count occurring variantsfixed morphology count occurring variantsfequency statistical association measures

feature identificationnon-compositional semantics word alignmentfixed syntax count occurring variantsfixed morphology count occurring variants

fequency statistical association measures

feature identificationnon-compositional semantics word alignmentfixed syntax count occurring variantsfixed morphology count occurring variantsfequency statistical association measures

CompositionalityThe most prominent feature of VMWEs is their non-compositionality:you cannot tell about the whole based on it’s parts.

But: not all MWEs are completely non-compositional.It can be di�cult to draw the line:

to cut the mustard

! to perform well

to sweep under the rug

! to hide

to spill the beans

! to reveal

(spill)

a secret

(the “beans”)

to bring somebody down

! to make somebody sad

to go ahead

! to start/proceed

to cut the mustard

! to perform well

! to hide

to spill the beans

! to reveal

(spill)

a secret

(the “beans”)

to go ahead

! to start/proceed

to cut the mustard

! to perform well

! to hide

to spill the beans

! to reveal

(spill)

a secret

(the “beans”)

to go ahead

! to start/proceed

to cut the mustard ! to perform well

! to hide

to spill the beans

! to reveal

(spill)

a secret

(the “beans”)

to go ahead

! to start/proceed

! to hide

to spill the beans

! to reveal

(spill)

a secret

(the “beans”)

to go ahead

! to start/proceed

to sweep under the rug ! to hide

to spill the beans

! to reveal

(spill)

a secret

(the “beans”)

to go ahead

! to start/proceed

to spill the beans

! to reveal

(spill)

a secret

(the “beans”)

to go ahead

! to start/proceed

to spill the beans ! to reveal

(spill)

a secret

(the “beans”)

to go ahead

! to start/proceed

to spill the beans ! to reveal (spill) a secret (the “beans”)

to go ahead

! to start/proceed

to go ahead

! to start/proceed

to bring somebody down ! to make somebody sad

to go ahead

! to start/proceed

to go ahead

! to start/proceed

to go ahead ! to start/proceed

Context

In some contexts, expressions that are taken to be VMWEs mightbe used compositionally. Imagine:

A soccer player kicking a bucket

A cat that has been caught in a bag and is later released

A janitor sweeping some dirt under some rug

A child spilling some beans on the floor

! not very likely, probably not very frequent, but not impossible!

! VMWE decisions have to be made context-dependently

Context

High Variety

VMWEs come in many di↵erent shapes, e.g.:

Idioms: let the cat out of the bag, spill the beans

Light-verb constructions: make a mistake vs. *do a mistake

Particle verbs: to bring down vs. Litto pick up

Inherently reflexive verbs:

sich enthalten (to abstrain) vs. Litenthalten (to contain)

High Variety

Problematic for many NLP applications

Everyone knows that VMWEs cause problems in NLP,but they are still often ignored in many applications.

many di↵erent shapes

long-distance dependencies between parts

data sparsity: many types not so many tokens

compositionality: where to draw the line?

translation: VMWEs do not always translate into VMWEs

Projects

Research on VMWEs:

di↵erent languages

di↵erent linguistic description levels

di↵erent applications

di↵erent approaches for identification(e.g. linguistics-based, heuristic, machine learning, ...)

Possible Projects:

identification of VMWEs

improved processing of VMWEs (e.g. in SMT)

determine the degree of compositionality of VMWEs

determine the presence of VMWEs in di↵erent contexts

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PARSEME

PARSEME = PARSing and Multi-word Expressions,a European project devoted to multiword expressions.http://typo.uni-konstanz.de/parseme/

upcoming shared task on identification of VMWEs

dates: t.b.a. February-March 2017

Workshop at EACL2017 in Valencia, Spain (April 2017)

Languages:

Germanic: English, German, Swedish, YiddishRomance: French, Italian, Romanian, Spanish, Brazilian PortugueseBalto-Slavic: Bulgarian, Czech, Croatian, Lithuanian, Polish, SloveneOther: Farsi, Greek, Hebrew, Hungarian, Maltese, Turkish

PARSEME

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PARSEME

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PARSEME

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PARSEME

Languages:

Questions?

language technology: research and development topic: verbal …nivre/master/intro_vmwe.pdf ·...

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