Toronto, Feb 17 (IANS) It may not be obvious, but hearing two languages regularly during pregnancy puts infants on the road to bilingualism by birth.

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.

Psychologists Krista Byers-Heinlein and Janet F. Werker of the University of British Columbia (UBC) along with Tracey Burns, Organisation for Economic Cooperation and Development, France, wanted to probe language preference 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).

Researchers employed a method known as 'high-amplitude sucking-preference procedure' to study the infants' language preferences.

This method capitalises 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 behaviour when they heard English than when they heard Tagalog being spoken.

However, bilingual infants had an equal preference for both English and Tagalog, says a university release.

These results suggest that prenatal bilingual exposure may affect infants' language preferences, preparing bilingual infants to listen to and learn about both languages.

These findings were published in Psychological Science.