Language learning may begin before birth

Babies may start to learn their mother tongues even before seeing their mothers’ faces. Newborns react differently to native and foreign vowel sounds, suggesting that language learning begins in the womb, researchers say.

Infants tested seven to 75 hours after birth treated spoken variants of a vowel sound in their home language as similar, evidence that newborns regard these sounds as members of a common category, say psychologist Christine Moon of Pacific Lutheran University in Tacoma, Wash., and her colleagues. Newborns deemed different versions of a foreign vowel sound to be dissimilar and unfamiliar, the scientists report in an upcoming Acta Paediatrica.

“It seems that there is some prenatal learning of speech sounds, but we do not yet know how much,” Moon says.

Fetuses can hear outside sounds by about 10 weeks before birth. Until now, evidence suggested that prenatal learning was restricted to the melody, rhythm and loudness of voices (SN: 12/5/09, p. 14). Earlier investigations established that 6-month-olds group native but not foreign vowel sounds into categories.

Moon and colleagues propose that, in the last couple months of gestation, babies monitor at least some vowels — the loudest and most expressive speech sounds — uttered by their mothers.