Perceptual learning of systematic variation in Spanish-accented speech.

Spoken language is characterized by an enormous amount of variability in how linguistic segments are realized. In order to investigate how speech perceptual processes accommodate to multiple sources of variation, adult native speakers of American English were trained with English words or sentences produced by six Spanish-accented talkers. At test, listeners transcribed utterances produced by six familiar or unfamiliar Spanish-accented talkers. With only brief exposure, listeners perceptually adapted to accent-general regularities in spoken language, generalizing to novel accented words and sentences produced by unfamiliar accented speakers. Acoustic properties of vowel production and their relation to identification performance were assessed to determine if the English listeners were sensitive to systematic variation in the realization of accented vowels. Vowels that showed the most improvement after Spanish-accented training were distinct from nearby vowels in terms of their acoustic characteristics. These findings suggest that the speech perceptual system dynamically adjusts to the acoustic consequences of changes in talker's voice and accent.