The influence of psychoacoustic and psycholinguistic factors on listener judgments of intelligibility of normal and Lombard speech

The influence of psychoacoustic and psycholinguistic factors on the intelligibility of Lombard speech compared to normal speech production was studied. When using additive white Gaussian noise and when the perceptual tests were performed on the complete vocabulary studied, confusable vocabularies (except the subset {m,n }) were less intelligible when produced in noise than when produced in quiet. This result was consistent among the different classes of listeners studied. Using multitalker noise as additive noise, it was found that there is a strong interaction between the type of noise used and the intelligibility scores obtained, and that female speakers are more intelligible than male speakers. Using a phoneme adjusted signal-to-noise ratio, it was observed, in agreement with acoustic analyses, that producing speech in noise can decrease the consonant-to-vowel energy ratio. The implications of these results for the development of robust speech recognizers are discussed