How Do Infants Become Experts at Native-Speech Perception?

Infants begin life ready to learn any of the world's languages, but they quickly become speech-perception experts in their native language. Although this phenomenon has been well described, the mechanisms leading to native-language-listening expertise have not. In this article, we provide an in-depth review of one learning mechanism: distributional learning (DL), which has been shown to be important in phonetic category learning. DL is a domain-general statistical learning mechanism that involves tracking the relative frequency of phonetic tokens in speech input. Although DL is powerful, recent research has identified limitations to it as well. We conclude with a discussion of possible supplementary phonetic-learning mechanisms, which focuses on the surrounding context in which infants hear phonetic tokens and how it can augment DL and highlight important linguistic differences between perceptually similar stimuli.