Phonetic Category Learning and Its Influence on Speech Production.

One of the hallmarks of any flexible system of perception and motor control is the ability to adjust to changes induced by dialect, development, fatigue, disease, or aging. Phonetic categories are an essential component of language that enables listeners and speakers to communicate effectively. Four studies are reviewed that illustrate how adults and infants adjust their phonetic categories rapidly and efficiently to maintain a tight coupling between speech perception and speech production. Although this process of adaptive plasticity takes place at the level of phonetic categories, it is also constrained by the lexicon. Words that share similar sounds or similar vocal-articulatory gestures impede the process of adaptation.