Non-native productions of Japanese single stops that are too long for one mora unit

The difficulty for non-native speakers in producing Japanese geminate stops with a long enough closure has been pointed out and extensively studied. However, the reverse problem exists for particular language speakers such as Chinese. For these speakers, production of Japanese intervocalic single stops sound like geminate stops. This study aimed to show acoustic evidence of this problem in the production of Japanese voiceless stops by learners of Japanese, and to compare speakers from different language groups, English, Chinese and French speakers. The results of the experiment indicated that since some of the stop productions by Americans and Chinese were too long for one mora unit, the Japanese heard a geminate (2 mora) instead of a single. Because French subjects had a small difference in the stop durations from the Japanese value, only a few of their productions of single stops were perceived as geminates. The language differences in timing pattern for Japanese stops were interpreted to reflect differences in timing implementation of native languages that is stress-timed and syllable-timed, at least concerning the difference between English and French speakers.