A focus on vowels in young human infants and animals: early sensitivities in language processing

Very early in life, from a few weeks to 5 months of age, human infants tend to focus on vowels over consonants to process words. In the present review, we discuss recent evidence suggesting that, just like young infants, nonhuman animals also tend to focus on vowels to identify sequences of sounds. This early use of vowels to recognize words might be linked to acoustic properties that are orthogonal to lexical processing. For example, vowels tend to be more salient than consonants, in the sense that vowels tend to be longer, more stable and are produced with more intensity than consonants. Thus, the recent data with nonhuman animals sheds a new light on this early stage of phoneme processing as the result of biological, and evolutionary relevant predispositions.