ACOUSTIC MANIFESTATIONS OF MORA TIMING IN JAPANESE

Segment durations in 20 minimal-paired words in Japanese were examined to identify regular patterns of acoustic manifestations of mora timin g in Japanese, The results indicate that segments consistently stretch or compress, providing temporal compensation within a mora and betwee n moras, to attain targeted length at the word level. A segment is 11% longer in the pre-geminate-stop position than in the pre-single-stop position; in the word final position, a segment is 9% shorter followin g a geminate stop than a segment following a single stop; and [t] in t he same phonotactic environment shows varied durations according to di fferent moraic conditions. Fricatives followed by a devoiced vowel are considerably longer than any other inherently long, nonmoraic segment s, and are comparable to moraic segments and the average mora duration . Syllable durations are not isochronous, varying by as much as 50%. T he word duration is affected more by the number of component sounds an d their inherent durations in two-mora than in three-or four-mora word s. When the word durations are converted into ratios, they are markedl y similar to the mora values. The results suggest a timing control mec hanism adjusting segments to obtain targeted word durations. These phe nomena describe mora timing in Japanese.