Development of a web framework for teaching and learning Japanese prosody: OJAD (online Japanese accent dictionary).

This paper introduces the first online and free framework for teaching and learning Japanese prosody including word accent and phrase intonation. This framework is called OJAD (Online Japanese Accent Dictionary) [1] and it provides three functions. 1) Visual, auditory, systematic, and comprehensive illustration of patterns of accent change (accent sandhi) of verbs and adjectives. Here only the changes caused by twelve kinds of fundamental conjugation are focused upon. 2) Visual illustration of the accent pattern of a given verbal expression, which is a combination of a verb and its postpositional auxiliary words. 3) Visual illustration of the pitch pattern of an any given sentence and the expected positions of accent nuclei in the sentence. The third function is implemented by using an accent change prediction module that we developed for Japanese text-to-speech (TTS) synthesizers [2, 3]. Experiments show that accent nucleus assignment to given texts by the proposed framework is much more accurate than that by native speakers. Subjective assessment and objective assessment by teachers and learners show very high pedagogical effectiveness of the framework. Index Terms: language education, Japanese prosody, accent sandhi, OJAD, speech synthesis, assessment experiments