A cross-linguistic study of diphthongs in spoken word processing in Japanese and English

Utilizing a phoneme‐monitoring task, the current study investigates the sensitivity to moraic structure in English and Japanese diphthongs by three groups of language users: monolingual Japanese listeners, monolingual English listeners, and semibilingual Japanese speakers of English. Experiment 1 focused on monolingual Japanese listeners and found that they did not show a moraic effect in English materials, although they did not show that in Japanese materials. Experiment 2 focused on monolingual English listeners and found that they were not sensitive to moraic structure in either English or Japanese, and seemed to listen to both English and Japanese in the same listening strategy. Experiment 3 focused semibilingual Japanese speakers of English and found that they showed a moraic effect in Japanese materials while they did not in English materials. Collectively, findings in experiments 1 and 3 suggest that Japanese natives are generally sensitive to moraic structure. Also, those in experiment 1 and 2 suggest that sensitivity to moraic structure is language specific. Finally, those in experiment 3 suggest that extensive second‐language experience allows one to readjust this tuning for each language spoken, such that a listener’s speech segmentation strategy can differ by language.