DEVELOPMENT OF PRECURSORS TO SPEECH IN INFANTS EXPOSED TO 2 LANGUAGES

The study of bilingualism has often focused on two contradictory possi bilities: that the learning of two languages may produce deficits of p erformance in each language by comparison with performance of monoling ual individuals, or on the contrary, that the learning of two language s may produce linguistic or cognitive advantages with regard to the mo nolingual learning experience. The work reported here addressed the po ssibility that the very early bilingual experience of infancy may affe ct the unfolding of vocal precursors to speech. The results of longitu dinal research with 73 infants aged 0;4 to 1;6 in monolingual and bili ngual environments provided no support for either a bilingual deficit hypothesis nor for its opposite, a bilingual advantage hypothesis. Inf ants reared in bilingual and monolingual environments manifested simil ar ages of onset for canonical babbling (production of well-formed syl lables), an event known to be fundamentally related to speech developm ent. Further, quantitative measures of vocal performance (proportion o f usage of well-formed syllables and vowel-like sounds) showed additio nal similarities between monolingual and bilingual infants. The simila rities applied to infants of middle and low socioeconomic status and t o infants that were born at term or prematurely. The results suggest t hat vocal development in the first year of life is robust with respect to conditions of rearing. The biological foundations of speech appear to be such as to resist modifications in the natural schedule of voca l development.