Infants 6-8 months old are able to identify nearly every speech sound contrast on which they have been tested, regardless of whether that contrast represents an across-category (two different phonemes) phonetic change in their native language or not. A child's ability to identify non-native consonant contrasts greatly diminishes by 11-12 months of age. The present study examined speech sound discrimination in three groups of listeners. Adult second language (L2) listeners of Spanish were compared with native English listeners with no knowledge of Spanish and native Mexican listeners to determine if they would show the ability to discriminate phonetic distinctions that are present in Spanish and not English. Behavioral and Electrophysiological measures were obtained in response to a continuum of bilabial consonant-vowel (CV) stimuli that differed in voice onset time (VOT) from -50 to 30 ms VOT (/ba/ to /pa/). The -50 ms VOT stimulus was paired with each of the others to form stimulus pairs with varying degrees of acoustic difference. Behavioral data showed that L2 listeners of Spanish perceived a transition from /ba/ to /pa/ later than native Spanish listeners but earlier than English only listeners. Electrophysiological data using the mismatch negativity revealed that the both L2 Spanish and native Spanish listeners perceived a distinction between stimuli in the stimulus pairs 20 ms earlier than English only listeners. These results support the theory that underlying neural-sensory representations of speech may be altered by linguistic experiences, and that the loss of non-native speech sound discrimination abilities in infancy and the regaining of these abilities in adulthood is not due merely to attentional bias.



College and Department

David O. McKay School of Education; Communication Disorders



Date Submitted


Document Type





Infants, Event Related Potentials, Voice Onset Time, Spanish, English, Electrophysiological, Second Language, Neurophysiologic