2018 Friday Poster 6551

Friday, November 2, 2018 | Poster Session I, Metcalf Small | 3pm

An exploration of language input and its impact on vocabulary development in bilingual infants
M. Carbajal, S. Peperkamp

Growing up in a bilingual environment is a unique experience: bilingual infants’ language background may differ in the amount of exposure to each language, the quality and quantity of speakers who provide input for each language, and the amount of within-speaker language mixing. Studies analyzing the impact of different aspects of the bilingual environment on language development in 2-year-olds yielded divergent results: Using an at-home Language Diary method, Place & Hoff (2011, 2015) found that English-Spanish bilingual toddlers’ language skills in each language correlate with the amount of exposure and the number of conversational partners in that language, whereas there was no effect of language mixing. By contrast, Byers-Heinlein (2012) examined parental code-mixing behavior and found that language mixing has a negative impact on vocabulary development. Here, we focus on an earlier stage, exploring different characteristics of 11-month-old infants’ bilingual input, and investigating how they may influence their receptive vocabulary.

Fifty-nine families with 11-month-old infants, who were regularly exposed to French and a second language (at least 20% exposure to each) participated. In contrast with the studies by Place & Hoff, this population lived in a largely monolingual community. To capture different aspects of the bilingual environment, we used both a questionnaire and a Language Diary method. For the latter, the caregivers kept throughout two days (one weekday, one weekend day) a report in blocks of 30 minutes of all the speakers who interacted with the child and the languages spoken by them. Language use was reported per speaker both for direct input (i.e., addressed to the child) and indirect input (i.e., addressed to other people). From the diaries, we derived 5 measures for both direct and indirect input: average percentage of French exposure, total number of French and L2 speakers, average language overlap within block, average by-speaker language overlap, and maternal percentage of French. Finally, to measure infants’ receptive vocabulary we used a short French CDI (Kern et al., 2010), and – when available – one in the L2 (N=24).

We found, first of all, good agreement between the diaries and parental questionnaires for both language input (r=0.70, p<.0001; Figure 1) and parental language use (r=0.95, p<.0001). While this suggests that both methods are equally reliable, the added value of diaries lies with the more detailed information they provide. Concerning language mixing, we found much variability, despite the fact that a great majority of families followed roughly a one-parent-one-language pattern. Particularly, infants with similar percentages of French exposure varied in how often the two languages co-occurred within each block, and how often individual speakers in their environment used both languages. Interestingly, the average by-speaker language overlap (that is, how often speakers used both languages within the same 30-minute block) had a negative impact on their receptive vocabulary in French (r=-0.37, p=0.006) and marginally so in L2 (r=-0.35, p=0.09) (Figure 2), in agreement with Byers-Heinlein (2012).

We conclude that from the earliest stages, vocabulary development is influenced negatively by language mixing in the bilingual infants’ input.

References

Byers-Heinlein, K. (2013). Parental language mixing: Its measurement and the relation of mixed input to young bilingual children’s vocabulary size. Bilingualism: Language and Cognition, 16(01), 32-48.

Kern, S., Langue, J., Zesiger, P., & Bovet, F. (2010). Adaptations françaises des versions courtes des inventaires du développement communicatif de MacArthur-Bates. Approche Neuropsychologique des Apprentissages chez l’Enfant, 107(108), 217-228.

Place, S., & Hoff, E. (2011). Properties  of  dual  language  exposure  that  influence  2-year-olds’  bilingual proficiency. Child development, 82(6), 1834-1849.

Place, S., & Hoff, E. (2015) Effects and noneffects of input in bilingual environments on dual language skills in 2½- year-olds. Bilingualism: Language and Cognition, 1023-1041.