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

The current study conducted three phoneme-detecting experiments in order to (1) provide further evidence for the Japanese listeners’ sensitivity to moraic structure and (2) treatment of diphthongs by three groups of language users (Japanese listeners, English listeners and semi-bilingual Japanese speakers of English). Japanese natives showed sensitivity to the moraic structure even when the moraic vowels are the second part of diphthongs. The results further showed that English listeners treat diphthongs as single units, while Japanese listeners treat them as two separate units. The semi-bilingual Japanese speakers of English treat diphthongs as single units in English but as separate units in Japanese.