a psycholinguistic perspective on child phonology sharon peperkamp emmanuel dupoux laboratoire de...

A Psycholinguistic Perspective on Child Phonology

Sharon Peperkamp

Emmanuel Dupoux

Laboratoire de Sciences Cognitives et Psycholinguistique, EHESS-CNRS, Paris

www.lscp.net/persons/peperkamp

Second International Conference on Contrast in Phonology. Toronto, May 3-5, 2002

Child phonology

Jakobsonian view of phonological acquisition:

Children’s productions– reflect their internal grammar– evolve from universally unmarked structures towards

the marked structures present in their language

Outline of talk

• Discuss problems with child phonology

• Propose a model of phonological processing, featuring:– a distinction between perception and production– a distinction between phonology and phonetics

• Show how in this model:– acquisition can take place– data of child phonology can be accounted for

I. Child phonology

Problem #1: Initial state• Children’s earliest productions

unmarked structures:- consonant: [p]

- vowel: [a]

- syllable structure: CV

• Infants’ perceptual capacities between 0 and 2 months

marked structures- [pa] vs. [ba] (Eimas et al. 1971)

- [a] vs. [i] (Trehub 1973)

- V vs. CV vs. VC ?

Are initial representations really unmarked?

Problem #2: Preverbal acquisition

• 6 months vowels (Kuhl et al. 1992; Polka & Werker 1994)

• 9 months phonotactics(Friederici & Wessels 1993; Jusczyk et al. 1993,

1994)

• 10-12 months consonants (Werker & Tees 1984)

Experimental perception data:

Is grammatical knowledge really reflected in production?

Two time paths in acquisition

0 12 months 4 years

adult-like

adult-like

Perception

Production

universal:marked

universal:unmarked

Two time paths in acquisition

0 12 months 4 years

adult-like

adult-like

Perception

Production

Do children acquire one or two grammars?

universal:marked

universal:unmarked

Problem #3: Speed of acquisitionAcquisition of syllable structure (Fikkert 1994)

Elke age onsets rhymes

1;6.4 stops, nasals fricatives

1;6.25 glides stops

1;7.22 nasals

1;9.24 fricatives

1;11.28 liquids

2;0.11 stop+glide

2;3.27 stop+liquid

2;4.15 [s]+stop

Why does acquisition take so long?

Problem #4: Inter-individual variability

Production of 3-syllable tokens by twins(Savinainen-Makkonen 2000)

1;5 1;6 1;7

Annika 0% 100% 100%

Antti 0% 27% 37%

Why do children follow different time paths?

Problem #5: Gradual changesConsonant harmony by Trevor (Pater & Werle 2001)

Why is learning gradual?

Regressive velar harmony

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

~1;5 1;6 1;7 1;8 1;9 1;10 1;11 2;0 2;1 2;2 2;3 2;4

Age

Pro

port

ion h

arm

oniz

ed

Problem #6: Intra-individual variability

• type variabilityfrequent words resist correction (Storkel & Gierut 2001)

consonant harmony in French child language

Hélène, 4;8.7: très [k] ‘very’ - trou [tu] ‘hole’

Why is there a frequency effect?

• token variabilitynon-frequent words show free variation

consonant harmony in English child language

Trevor, 2:1.5: truck [trk] ~ [krk]

Why is there type-specific variability?

II. A theory of phonological acquisition

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

Phonological processing

|thi|

[thi]

/ti/ /ti/

[thi]

|thi|

Initial statePerception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding:

phonological decoding:

phonetic decoding: identity

phonetic encoding:

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

Step 1 Step 3

Step 2

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

Step 1

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

bottom-up algorithms- segments (Kuhl et al. 1997; Maye,

Werker & Gerken in press)

- syllable structure (Peperkamp 2001)

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

0-12 months

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

0-12 months

Step 2

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

0-12 months

bottom-up algorithms - allophonic rules (Peperkamp & Dupoux 2002)

- neutralizing rules (Peperkamp & Dupoux 2002)

- stress (Dupoux & Peperkamp 2002)

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

0-12 months

12 months - ??

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

0-12 months Step 3

12 months - ??

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

0-12 months

12 months - ??

trial and error algorithms(Boersma 1999)

Perception Production

underlying form underlying form

Phonology

surface form surface form

Phonetics

universal phonetic motor planrepresentation

acoustic signal acoustic signal

phonological encoding

phonetic encoding

phonological decoding

phonetic decoding

0-12 months 1-4 years

12 months - ??

surface form

motor plan

assembling rules retrieval from storage

Dual route for phonetic encoding

(Levelt 1989)

surface form

motor plan

Stage 1

[t, k] |k|

Creation of simplifying assembling rules

‘very’: [t] |k| assembled

‘hole’: [tu] |ku| assembled

surface form

motor plan

[t] |k|

Stage 2

[t, k] |k|

Storage of patterns

‘very’: [t] |k| assembled

‘hole’: [tu] |ku| assembled

surface form

motor plan

[t] |k|

Stage 2

[t, k] |k|

Storage of patterns

‘very’: [t] |k| retrieved from storage

‘hole’: [tu] |ku| assembled

surface form

motor plan

[t] |k|

Stage 3

[t, k] |t, k|

Correction of assembling rules

‘very’: [t] |k| retrieved from storage

‘hole’: [tu] |ku| assembled

surface form

motor plan

[t] |k|

Stage 3

[t, k] |t, k|

Correction of assembling rules

‘very’: [t] |k| retrieved from storage

‘hole’: [tu] |tu| assembled

surface form

motor plan

[t] |t|

Stage 4

[t, k] |t, k|

Correction of stored patterns

‘very’: [t] |k| retrieved from storage

‘hole’: [tu] |tu| assembled

surface form

motor plan

[t] |t|

Stage 4

[t, k] |t, k|

Correction of stored patterns

‘very’: [t] |t| retrieved from storage

‘hole’: [tu] |tu| assembled

Summary: phonetic encoding and children’s productions

Why does acquisition take so long?articulation is a complex motor skill

Why do children follow different time paths?the phonetic encoder is acquired by means of trial and error algorithms, which predict variation among individuals

Why is learning gradual?motor skills are learned with ups and downs

Why is there a frequency effect?during the acquisition of the phonetic encoder, the correction of stored patterns is more difficult for more frequent patterns

Why is there type-specific variability?there is competition both between and within the two routes, the outcome of which depends on both linguistic (e.g. utterance length) and extra-linguistic factors (e.g. fatigue)

Conclusion

• Models of phonological acquisition should take both perception and production data into account.

• Phenomena of ‘child phonology’ reflect the developing phonetic encoder.

• The phonetic encoder is partly non-linguistic; it should, therefore, be modeled within a psycholinguistic framework.