Aspects of final consonant production in American English by nonnative speakers

This paper describes the production of word-final, utterance-medial /t, d/ in American English by native speakers and by three groups of nonnative speakers of English. Twenty-four nonnative subjects, whose native languages include Arabic, Korean, Spanish, and Thai, were rated by native English speakers as having no accent, a mild accent, or a medium to heavy accent in English. Measurement of five tokens each of /t/ and /d/ for each speaker and for 6 native English speakers were compared. Neither the Americans nor any of the nonnative groups significantly differentiated /t/ from /d/ by closure duration. As strength of accent rating increased, mean closure duration tended to increase. Also, as strength of accent rating increased, implementation of manner of stop consonant production (including flapping and aspirated versus nonaspirated release) tended to change. Results suggest that both duration and the ability to produce a number of durationally different release options in English may affect the degree of perceived foreignness.