In order to accelerate the promotion of speech recognition systems to the public; understanding characteristics of speech in real environments is one of the most important issues. This paper reports variations of speech characteristics in a car environment. To analyze speech characteristics in the specific environment, a corpus, recorded carefully in terms of equality of utterances and conditions for whole set of speakers, is necessary. We created a new corpus named "Drivers' Japanese Speech Corpus in a Car Environment (DJS-C)": composed of utterances of words useful for the operation of in-vehicle information appliances. Analysis of the DJS-C corpus shows that differences in speech characteristics are diverse among drivers and change with driving conditions. Quantitative analysis and speech recognition experiments show that performance degrades due to Distance between Phonemes, Uniqueness of Speaker's Voice, and SNNR.
Bibliographic reference. Kato, Tomoyuki / Okamoto, Jun / Shozakai, Makoto (2008): "Analysis of drivers' speech in a car environment", In INTERSPEECH-2008, 1634-1637.