2018 Fiscal Year Final Research Report

Comparing the comprehensiveness of English speech with the degree of Japanese accent using synthesized Japanese-English bilingual speech

Research Project

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Project/Area Number	15H02729
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	Perceptual information processing
Research Institution	Waseda University
Principal Investigator	Kondo Mariko 早稲田大学, 国際学術院, 教授 (00329054)
Co-Investigator(Kenkyū-buntansha)	山岸順一国立情報学研究所, コンテンツ科学研究系, 准教授 (70709352)
Research Collaborator	Henter Gustav Eje
Project Period (FY)	2015-04-01 – 2019-03-31
Keywords	第二言語音声習得 / バイリンガル音声 / 英語音声習得 / 第二言語音声評価 / 音声知覚
Outline of Final Research Achievements	Japanese accented English pronunciation was studied in terms of speech communication by native and non-native English speakers. The focus of the study is to examine if Japanese accented English is easily understood by other language speakers and whether the necessary information is conveyed to listeners. First, acoustic details of Japanese accented English were examined using a large-scale speech corpus. Based on these findings, Japanese accented English was synthesized by changing the degree of Japanese accentedness of some English phonemes using the Cyborg speech synthesis system, developed based on deep-learning-based speech synthesis. Then perception tests were performed to investigate segmental accuracy and Japanese accentedness. We found that assessors’ first language had little effect on the comprehension of the Japanese accented English. The results suggest that new pronunciation teaching systems need to be developed that focus on improving segmental accuracy.
Free Research Field	音声学、第二言語音声習得、音声コーパス
Academic Significance and Societal Importance of the Research Achievements	本研究は、これから益々一般的となる非母語話者間の音声コミュニケーションにおいて、すでに数多くの研究が行われている学習者としての発話理解・意思の疎通だけではなく、“情報を伝達する側”という視点で、英語母語話者・非母語話者を問わず誰にでも通じる日本語訛の英語とは何か、どのような発音であれば、母語を問わず誰にとっても理解されるのかを客観的に示し、英語音声習得教育の指針を示すことを目指した研究である。外国語訛があっても必ずしも理解度が低くなるわけではなく、母語話者のように話せるようになる教育よりも、必要な情報を伝えられる音声コミュニケーションを想定した外国語音声教育が大切なことが分かった。