Rhythmic cues and possible-word constraints in Japanese speech segmentation

In two word-spotting experiments, Japanese listeners detected Japanese word s faster in vowel contexts (e.g.. aguru to sit cross-legged. in oagura) tha n in consonant contexts (e.g tagura). In the same experiments, however, lis teners spotted words in vowel contexts (e.g.. saru. monkey, in sarua) no fa ster than in moraic nasal contexts (e.g.. saruN). In a third word-spotting experiment, words like uni. sea urchin, followed contents consisting of a c onsonant-consonant-vowel mora (e.g., gya) plus either a moraic nasal (gyaNu ni) a vowel (gyaouni) or a consonant (gyabuni). Listeners spotted words as easily in the first as in the second content (where in each case the target words were aligned with mora boundaries), hut found it almost impossible t o spot words in the third (where there was a single consonant, such as the [b] in gyabuni, between the beginning of the word and the nearest preceding mora boundary). Three control experiments confirmed that these effects ref lected the relative ease of segmentation of the words from their contexts. We argue that the listeners showed sensitivity to the viability of sound se quences as possible. Japanese wr,rds in the way that they parsed the speech into words. Since single consonants are not possible Japanese words, the l isteners avoided lexical parses including single consonants and thus had di fficulty recognizing words in the consonant contexts. Even though moraic na sals are also impossible words. they were not difficult segmentation contex ts because. as with the vowel contexts, the mora boundaries between the con texts and the target words signaled likely word boundaries. Moraic rhythm a ppears to provide Japanese listeners With important segmentation cues. (C) 2001 Academic Press.