The Cognitive Unit of Segmentation for Speech in Japanese

We performed a cognitive experiment in order to obtain evidence that prosody is used for the segmentation of continuous speech for understanding in real time. We assume that the cognitive unit in Japanese speech is the accentual phrase (AP) which is represented by low and high pitch patterns according to the Japanese accent rule. Meaningless speech which consisted of two APs was used as the experimental materials. Since 4-morae AP and 5-morae AP were used, there were 20 possible APpairs consisting of 4-morae + 5-morae and 20 possible AP-pairs consisting of 5-morae + 4-morae. Twenty-four participants listened to these speech materials with 9morae and were asked to judge whether they sounded like 4-morae + 5-morae or 5-morae + 4-morae. In the case of speech material in which only one judgment follows the Japanese accent rule, 93.4% of the ratings followed th accent rule. This result led to the conclusion that cognitive segmentation followed the Japanese accent rule.