Automatic evaluation of English spoken by Japanese students
Jared Bernstein, Mitchel Weintraub, Mike Cohen, Hy Murveit · The Journal of the Acoustical Society of America · 1989
The paper describes the methods and results of a study of the feasibility of automatically grading the performance of Japanese students when reading English aloud. SRI recorded 31 adult Japanese speakers: 22 men and 9 women. Each Japanese speaker read six sentences aloud. All 186 recorded utterances were presented in a random order for rating by three expert listeners who rated the utterances on two occasions. Speech-grading software was developed from an adaptive hidden-Markov-model (HMM) speech-recognition system. The grading procedure is a two-step process: First, the speech to be graded is aligned, then the segments of the speech signal that are located are compared with models of those segments that have been developed from a database of speech from native speakers of English. Important points in the results are: (1) ratings of speech quality by expert listeners are extremely reliable, and (2) automatic grades from the system correlate well (>0.8) with those ratings.