Study: Bilingual babies learn in prenatal period

Hearing two languages with regularity during pregnancy can put an infant on the road to bilingualism by the time of birth.

A study in Psychological Science (a journal of the Association for Psychological Science) found that babies born to mothers who spoke two languages regularly during their pregnancy showed different language preferences at birth over those infants whose moms only spoke one language. Psychological scientists Krista Byers-Heinlein and Janet F. Werker from the University of British Columbia, and Tracey Burns of the Organization for Economic Co-operation and Development in France investigated language preference and discrimination in newborns. The experiments were tested on two groups of newborns: babies whose mothers spoke just English during pregnancy, and babies whose moms spoke both Tagalog (a language from the Philippines) and English.

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.

During the first experiment the babies heard 10 minutes of speech, alternating each minute between English and Tagalog. The babies who had heard only English during pregnancy showed increased sucking behavior when they heard English being spoken rather than Tagalog. On the other hand, the babies born to bilingual moms had an equal preference for both languages.

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.

The next experiment was to find out if the bilingual babies could distinguish between the two languages, the crucial aspect of being able to learn multiple languages. Sentences were spoken in one language to the newborns until they lost interest. Then sentences were spoken in the other language, or a different person spoke the same language to them. The babies' sucking increased if they heard the other language spoken once they lost interest in hearing the first language. If they heard more of the same language their sucking did not increase.

These results suggest that bilingual infants, along with monolingual infants, are able to discriminate between the two languages, providing a mechanism from the first moments of life that helps ensure bilingual infants do not confuse their two languages.