Language learning in bilinguals’ early development

One fact about humankind is that a large portion of human beings on this earth speaks more than one language. As mentioned before, our speech perception abilities undergo a binary modification towards the end of the first year of life in that our ability to differentiate between non-native contrasts decreases.  The question therefore arises what impact a bilingual context would have on such a typical phonetic development? Would the impact vary depending on whether an infant learns the second language at the same time as the first language or shortly after the first language?

Bilinguals who were exposed to their first (L1) and second (L2) languages from birth, are known as simultaneous bilinguals (Meisel, 1989). Simultaneous bilinguals differ from bilinguals who learned their second language when their lexical and phonological knowledge of their first language had already partially established. Those bilinguals are known as sequential bilinguals. While sequential bilingualism is considered to cause a transfer from the first onto the second language, simultaneous bilingualism is marked by both languages evolving relatively autonomously from one another (de Houwer, 2005; Meisel, 1989, 2001).

Since children will have lost their sensitivity to non-native speech sounds by the end of the first year of life, in sequential bilingualism, when children are exposed to the second language, they will need to regain their sensitivity to the non-native phonetic sounds including sounds that are distinct in the second language. For example, a child with Japanese as L1, who is now learning English as L2, would need to restore the perceptual difference between speech sounds /r/ and /l/ that in contrast to English language, belong to the same phonetic category in the Japanese language (Goto, 1971; Miyawaki et al., 1975). This way, they will be able to differentiate between /l/ and /r/, and understand that, for example, ‘lead’ and ‘read’ are words in English that differ in meaning.

What does the situation look like in simultaneous bilinguals who grew up in a bilingual language environment since birth? Previous research showed that infants are able to create and learn phonetic categories and contrasts because they are sensitive to how the phonetic values of the phonetic elements are statistically distributed in a language system (Maye, Werker and Gerken, 2002). Then, what is the impact of this sensitivity to how speech sounds are statistically distributed in the language input on infants who grew up in a bilingual context? If the role of continued exposure to contrasts in both languages is important, this would mean that by the age of 8 months, infants as simultaneous bilinguals would have created two phonetic categories. However, a distributional overlap between two contrasts in one language and one speech sound in the other language that represents an acoustically intermediate speech sound may give rise to a single extended phonetic category in the simultaneous bilingual infants that includes all three speech sounds (Bosch & Sebastian-Galles, 2003 a, b). The simultaneous bilingual infant would then have difficulties discriminating between these sounds.

This would imply that compared to monolingual infants’ perceptual abilities, simultaneous bilingual infants’ ability to create contrastive categories that are particular to a language is postponed by this cross-language distributional overlap of speech sounds. Researchers predicted that the extent to which speech sounds occur in both languages, i.e. the frequency occurrence of speech sounds, may counteract the impact that this delay has on bilingual infants’ discrimination ability (Sundara et al., 2008). They compared monolingual English infants’, monolingual French infants’ and bilingual French-English infants’ discrimination ability of English and French instances of /d/ (Sundara et al., 2008). They found that due to the high frequency of specific speech sounds tested, similar to monolingual English infants, bilingual 10-12 month olds were able to differentiate between different exemplars of French and English /d/ in spite of overlapping distributions of French and English /d/ (Sundara et al., 2008). Thus, apart from confirming previous evidence that statistical distributional learning assists infants in language learning (Saffran, 2003), the results specifically suggest that for a particular phonetic contrast, the question whether bilinguals follow a different developmental trajectory from matched monolingual controls depends on how frequent speech sounds from phonetic categories occur in actual speech, and on their cross-language distributional overlap.

References

Bosch, L., Sebastian-Galles, N. (2003a). Language experience and the perception of a voicing contrast in fricatives: Infant and adult data. In M.J. Sole, D. Recasens, & J. Romero (Eds.), Proceedings of the 15th International Congress of Phonetic Sciences (pp. 1987-1990). Barcelona: Causal Productions.

 

De Houwer, A. (2005).  Early bilingual acquisition: Focus on morphosyntax and the Separate Development Hypothesis. In J.F. Kroll  & A. M. B. de Groot (Eds.), Handbook of bilingualism: Psycholinguistic approaches (pp.30-48). New York: Oxford University Press.

Goto, H. (1971). Auditory perception by normal Japanese adults of the sounds L and R. Neuropsychologia, 9, 317-323.

Maye, J. Werker, J.F., & Gerken, L. (2002). Infant sensitivity to distributional information can affect phonetic discrimination. Cognitive Psychology, 82, B101-B111.

 

Meisel, J. (1989). Early differentiation of languages in bilingual children. In K. Hyltenstam & L. Obler (Eds.), Bilingualism across the lifespan. Aspects of acquisition, maturity and loss (pp. 13-40). Cambridge, UK: Cambridge University Press.

Meisel, J. M. (2001). The simultaneous acquisition of two first languages: Early differentiation and subsequent development of grammars. In J. Cenoz& F. Genese (Eds.), Trends in bilingual acquisition (pp.11-41). Amsterdam/Philadelphia: John Benjamins.

Miyawaki, K., Strange, W., Verbrugge, R., & Liberman, A. M. (1975). An effect of linguistic experience: The discrimination of [r] and [l] by native speakers of Japanese and English. Perception & Psychophysics, 18, 331-340.

Saffran, J.R. (2003). Statistical language learning: Mechanisms and constraints. Current Directions in Psychological Science, 12, 110-114.

Sundara, M., Polka, L., & Molnar, M. (2008). Development of coronal step perception: Bilingual infants keep pace with their monolingual peers. Cognition, 108, 232-242.