All tongues, but what an infant hears, becomes foreign

     Most of us have heard the claim that infants can produce the sounds of any language before they learn which small subset of that universal inventory their own language requires. Actually, this claim isn’t quite true. All infants find some speech sounds easier to produce than others. Vowels are easy, as are consonant sounds such as “b,” “n,” or “d.”  Fricatives (“f,” “th,”  etc), affricates (“ch”), and                liquids (“r,” “l,”) are universally harder to produce and are, therefore, relatively rare at this early stage.

     On the other hand, a very young infant does have a remarkable ability to hear all the sounds, and differences in sounds, exploited by any of the world’s  3,000 languages – despite the fact that most of those distinctions are ones their own mother tongue doesn’t use. For example, a four-month-old Japanese infant can easily differentiate an “l” from an “r” sound, even if the parents can’t.  And an American four-month-old  born into an English-language environment can discern differences between Chinese-language tones that are beyond the abilities of its parents.

     What quickly begins to happen, though, is that the infant’s ears become less acute. Of course, it’s not literally the ears that are changing, but the brain, which is adjusting its phonetic-perception circuitry to the needs of just one language.