Speech assistive technology to improve the interaction of dysarthric speakers with machines

In this paper, we propose a communication scheme using automatic speech recognition and speech synthesis in order to assist dysarthric speakers. This system aims at improving recognition rate and intelligibility of dysarthric speech. An HMM-based recognizer using variable duration of Hamming window permits to raise the recognition rate of dysarthric speech up to 80 %. In order to improve the intelligibility of synthetic speech while keeping the naturalness close to the voice of dysarthric speaker, we synthesize the recognized text using new basic unit segmenter, a new concatenating algorithm and a grafting technique to correct the bad pronounced phonemes. The NEMOURS dysarthric database is used to evaluate the proposed assistive communication system. Results show that a rate of 65 % to 80% of correct word recognition and a Mean Opinion Score (MOS) of 4 were obtained.