Bilingual babies: The roots of bilingualism in newborns
February 16, 2010

It may not be obvious, but hearing two languages regularly during pregnancy puts infants on the road to bilingualism by birth. According to new findings in Psychological Science, a journal of the Association for Psychological Science, infants born to bilingual mothers (who spoke both languages regularly during pregnancy) exhibit different language preferences than infants born to mothers speaking only one language.

Psychological scientists Krista Byers-Heinlein and Janet F. Werker from the University of British Columbia along with Tracey Burns of the Organization for Economic Co-operation and Development in France wanted to investigate language preference and discrimination in newborns. Two groups of newborns were tested in these experiments: English monolinguals (whose mothers spoke only English during pregnancy) and Tagalog-English bilinguals (whose mothers spoke both Tagalog, a language spoken in the Philippines, and English regularly during pregnancy). The researchers employed a method known as "high-amplitude sucking-preference procedure" to study the infants' language preferences. This method capitalizes on the newborns' sucking reflex — increased sucking indicates interest in a stimulus. In the first experiment, infants heard 10 minutes of speech, with every minute alternating between English and Tagalog.

Results showed that English monolingual infants were more interested in English than Tagalog — they exhibited increased sucking behavior when they heard English than when they heard Tagalog being spoken. However, bilingual infants had an equal preference for both English and Tagalog. These results suggest that prenatal bilingual exposure may affect infants' language preferences, preparing bilingual infants to listen to and learn about both of their native languages.