Age of Acquisition and Proficiency as Factors in Language Production:

Agreement in Bilinguals

Rebecca Foote

February 21, 2007

Univ. of Illinois at Urbana-Champaign

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Central question in SLA

Why is the outcome of second language (L2) acquisition different from that of first language (L1) acquisition?

Specifically, why is success inevitable in L1 acquisition but failure to become nativelike the standard for L2 learners (late bilinguals)?

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Age effects in language acquisition

Critical period hypothesis– Critical / sensitive period for language learning:

“a limited developmental period during which it is possible to acquire a language, be it L1 or L2, to normal, nativelike levels” (Birdsong, 1999)

But does this apply to all aspects of language acquisition?

Are there particular linguistic structures or psycholinguistic processes that are not susceptible to age effects?

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What is it that’s not nativelike about L2 learners (late bilinguals)?

Variability in late bilingual production of agreement morphology:– Example:

Jim runs to the store. *Jim run to the store.

Two possible sources for the problem:– Deficit in linguistic knowledge (competence)

Beck (1998), Eubank, (1994), Hawkins & Chan, (1997), Meisel (1990, 1997), Schachter (1989, 1990)

– Psycholinguistic processes of language production (performance) Lardiere (1998a, 1998b), Prévost & White (2000), Fernández (1999)

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What about early bilinguals?

Don’t seem to show same morphological variability as late bilinguals

Don’t always pattern with monolinguals– Kohnert, Bates, & Hernández (1999), Montrul (2002)

Are they more accurate in language processing and production than late bilinguals?

What if they are not of “nativelike” proficiency?

Experimental study: Subject-verb number

agreement production in English-Spanish bilinguals

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Subject-verb number agreement production in Spanish and English

Verb number controlled by the number of the subject noun phrase

– The cats are black. – Los gatos son negros.– The lamp is beautiful. – La lámpara es bella.

But how do we account for subject-verb number agreement errors (The occurrence of these errors are underestimated)?

– Agreement potentially influenced by: Grammatical number of the subject noun phrase “Notional” or “conceptual” number of the subject noun phrase Attraction Conceptual number and attraction working together

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Grammatical vs. conceptual number

Grammatical number– Lexically specified number of head noun

Conceptual number– Number of referent in the speaker’s mental model – one

thing or more than one thing? Singular or plural?

– Jeans– Faculty– Family– Clothes– Clothing

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Attraction

*The tree behind the houses ARE large. Error common to native speakers of both

Spanish and English – (Bock & Miller, 1991; Vigliocco, Butterworth, &

Garrett, 1996)

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Conceptual number and attraction working together

Single referent complex NP:– The bus to the schools…

Distributive referent complex NP:

– The label on the bottles… Distributivity effects in subject-

verb number agreement– The label on the bottles are…

vs.

– The bus to the schools are…

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Subject-verb number agreement production in Spanish and English

Psycholinguistic research on agreement production– Speech error research – determine which factors

play a role Grammatical number only? Conceptual number as well?

– Bock & Miller (1991) Sentence-fragment completion methodology

– “The label on the bottles…”

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Cross-linguistic differences in subject-verb number agreement production

English:– Grammatical number (no distributivity effects) – Bock &

Miller (1991) The label on the bottles are… = The bus to the schools are…

Spanish:– Conceptual number as well as grammatical number

(distributivity effects) – Vigliocco, Butterworth, & Garrett (1996)

The label on the bottles are… > The bus to the schools are…

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Maximalist model of agreement production (Vigliocco, Butterworth, & Garrett, 1996)

Interactive model that assumes a language production system with various levels or steps (Levelt, 1989; 1999)

– Message conceptualization – Grammatical encoding – Morphophonological encoding – Phonetic encoding– Articulation

Accuracy of agreement production ensured by system’s use of the maximal amount of information available to it; information across levels or steps is shared

Accounts for cross-linguistic differences in the influence of conceptual number on agreement production by proposing different mechanisms of agreement for different languages

– English: Feature copying– Spanish: Feature unification

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Maximalist model of agreement production – feature copying(from Vigliocco, Butterworth, & Garrett, 1996, p. 270)

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Maximalist model of agreement production – feature unification(from Vigliocco, Butterworth, & Garrett, 1996, p. 271)

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Maximalist model of agreement production –cross-linguistic differences

Languages with richer inflectional morphology, flexible word order and the possibility of null subjects are more likely to produce agreement by means of feature unification and therefore to show conceptual effects in agreement production

Languages with poorer inflectional morphology, less flexible word order and little possibility of null subjects are more likely to produce agreement by means of feature copying, and therefore to show no conceptual effects in agreement production

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Agreement production in bilinguals

How do cross-linguistic differences play out in bilingual agreement production?– Cause of variability in late bilingual production of

agreement morphology? Proficient bilinguals appear to process and

produce agreement in the same way in both of their languages– Nicol, Teller, & Greth (2001)– Nicol & Greth (2003)

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Experimental study

Experiment 1 – Agreement production in English and Spanish monolinguals

Experiment 2 – Agreement production in English-Spanish bilinguals

Experiment 1: Monolinguals

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Experiment 1: Research Question

Are there differences in the mechanics of subject-verb number agreement production in Mexican Spanish, Dominican Spanish, and English?

– Previous research indicates cross-linguistic differences between Spanish and English (Vigliocco, Butterworth, & Garrett, 1996) with respect to the factors that influence singular or plural agreement

Grammatical number Conceptual number

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Experiment 1: Participants

English monolinguals (n = 18) Mexican Spanish monolinguals (n = 32) Dominican Spanish monolinguals (n = 28)

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Experiment 1: Materials

Language history questionnaire Experimental task

– Modified sentence-fragment completion task

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Experiment 1: Stimuli

Auditory stimuli– 2 sets (1 English, 1 Spanish), 32 complex subject noun phrases– 16 with distributive referents as head nouns

The label on the bottles– 16 with single referents as head nouns

The bus to the schools– 64 filler subject noun phrases

The chairs Pictorial stimuli

– Each fragment associated with a line drawing of its referent Example: The stamp on the envelopes

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Experiment 1: Procedure

Participants see a picture in the center of the computer screen, followed by a sentence fragment played over the speakers

Repeat and complete fragment as quickly and accurately as possible, naming the color of the head noun’s referent

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Experiment 1: Example trial

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Experiment 1: Results

Participants’ responses digitally recorded, transcribed, and coded for errors

Predictions– If participants are sensitive only to grammatical number,

they will make approximately the same number of errors with single and distributive referent fragments.

The label on the bottles are… = The bus to the schools are…– If participants are sensitive to conceptual number, they will

make more errors with distributive referent fragments than with single referent fragments.

The label on the bottles are… > The bus to the schools are…

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Experiment 1: ResultsAre participants sensitive only to grammatical number, or to conceptual number also?

Net Error Rates by Fragment Type

0

5

10

15

20

25

30

35

40

45

50

English Mexican Spanish Dominican Spanish

Single

Distributive

The label on the bottles are… > The bus to the schools are…

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Experiment 1: Research Question

Are there differences in the mechanics of subject-verb number agreement production in Mexican Spanish, Dominican Spanish, and English?– NO…All three languages/dialects evidence

conceptual effects in agreement production

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Experiment 1: Discussion

English, Dominican Spanish, and Mexican Spanish all show sensitivity to conceptual number in agreement production– In terms of the maximalist model (Vigliocco,

Butterworth, & Garrett, 1996), all three effect agreement by means of feature unification

Experiment 2: Bilinguals

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Experiment 2: Research questions

Do English-Spanish bilinguals produce subject-verb number agreement in the same manner in both languages?

What role do age of acquisition and proficiency play in bilingual agreement production?– Manner – Accuracy

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Experiment 2: Participants

Early English-Spanish bilinguals (age of acquisition of both languages < 5)– Intermediate proficiency – 16– Advanced proficiency – 22

Late English-Spanish bilinguals (age of acquisition of Spanish > 11)– Intermediate proficiency – 52– Advanced proficiency – 18

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Experiment 2: Materials

Language history questionnaire Proficiency test(s) Experimental task

– Modified sentence-fragment completion task

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Experiment 2: Stimuli & Procedure

Same as Experiment 1 – Completed in both English and Spanish –

different list each time, sessions at least 1 week apart

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Experiment 2 Results: MannerAre English-Spanish bilinguals sensitive only to grammatical number when producing English?

Net error rates by fragment type - English

0

5

10

15

20

25

30

35

Early-Intermediate Early-Advanced Late-Intermediate Late-Advanced

Single

Distributive

The label on the bottles are… > The bus to the schools are…

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Experiment 2 Results: MannerAre English-Spanish bilinguals sensitive to conceptual number when producing Spanish?

Net error rates by fragment type - Spanish

0

5

10

15

20

25

30

35

Early-Intermediate Early-Advanced Late-Intermediate Late-Advanced

Single

Distributive

The label on the bottles are… > The bus to the schools are…

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Experiment 2 Research questions: Manner

Do English-Spanish bilinguals produce subject-verb number agreement in the same manner in both languages?

– YES

What role do age of acquisition and proficiency play in bilingual agreement production?

– Manner NONE…all groups are sensitive to conceptual number in both

Spanish and English

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Experiment 2 Discussion: Manner

Results support NO cross-linguistic differences in how bilinguals produce agreement…conceptual number affects agreement processes in both English and Spanish regardless of age of acquisition or proficiency level.

– In terms of the maximalist model (Vigliocco, Butterworth, & Garrett, 1996), bilinguals effect agreement by means of feature unification in both of their languages, no matter the AoA or proficiency level

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Experiment 2 Results: Accuracy – AoAAre early bilinguals more accurate in agreement production than late bilinguals?

Overall Agreement Error Rates Early vs. Late Bilinguals

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

English Spanish

Early Bilinguals Late Bilinguals

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Experiment 2 Results: Accuracy – ProficiencyAre advanced bilinguals more accurate in agreement production than intermediate bilinguals?

Overall Agreement Error Rates Intermediate vs. Advanced Bilinguals

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

English Spanish

Intermediate Bilinguals Advanced Bilinguals

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Experiment 2 Research questions: Accuracy

What role do age of acquisition and proficiency play in agreement production in English-Spanish bilinguals’ two languages?– Accuracy

More proficient bilinguals are more accurate, no matter whether late or early

Early bilinguals less accurate than late bilinguals

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Experiment 2 Discussion: Accuracy

Advanced proficiency bilinguals more accurate than intermediate proficiency bilinguals

Early bilinguals NOT more accurate than late bilinguals…other way around.– Contrary to an across-the-board interpretation of

the CPH

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Central question in SLA

Why is the outcome of second language (L2) acquisition different from that of first language (L1) acquisition?

– Variability in late bilingual production of agreement morphology– Psycholinguistic processes of language production (performance)

as a source of the variability The aspects of the agreement production system investigated

are not responsible for the variability at the level of inflectional morphology present in bilinguals

Is there really a problem with morphological variability in late bilingual agreement production?

– Subject-verb number agreement vs. adjective agreement Adjective agreement in Spanish: La etiqueta en las botellas es roja.

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Subject-verb number agreement vs. adjective agreement errors

Overall Agreement Error Rates - Number vs. Adjective Early vs. Late Bilinguals

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

Number Adjective

Early Bilinguals Late Bilinguals

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Conclusion

Age effects in second language acquisition should be investigated in terms of specific linguistic structures or psycholinguistic processes

Younger may not always be better!

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Acknowledgements

Silvina Montrul J. Kathryn Bock Ann Abbott Melissa Bowles Jonathan Foote Justin Davidson Dept. of Spanish, Italian, and Portuguese, University

of Illinois at Urbana-Champaign University of Illinois Graduate College

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Thank you!

Questions? Comments?