Training the perception of Hindi dental and retroflex stops by native speakers of American English and Japanese.

Perception of second language speech sounds is influenced by one's first language. For example, speakers of American English have difficulty perceiving dental versus retroflex stop consonants in Hindi although English has both dental and retroflex allophones of alveolar stops. Japanese, unlike English, has a contrast similar to Hindi, specifically, the Japanese /d/ versus the flapped /r/ which is sometimes produced as a retroflex. This study compared American and Japanese speakers' identification of the Hindi contrast in CV syllable contexts where C varied in voicing and aspiration. The study then evaluated the participants' increase in identifying the distinction after training with a computer-interactive program. Training sessions progressively increased in difficulty by decreasing the extent of vowel truncation in stimuli and by adding new speakers. Although all participants improved significantly, Japanese participants were more accurate than Americans in distinguishing the contrast on pretest, during training, and on posttest. Transfer was observed to three new consonantal contexts, a new vowel context, and a new speaker's productions. Some abstract aspect of the contrast was apparently learned during training. It is suggested that allophonic experience with dental and retroflex stops may be detrimental to perception of the new contrast.