Speakers can adopt a speaking style that allows them to be understood more easily in difficult communication situations, but few studies have examined the acoustic properties of clearly produced consonants in detail. This study attempts to characterize the adaptations in the clear production of American English fricatives in a carefully controlled range of communication situations. Ten female and ten male talkers produced fricatives in vowel-fricative-vowel contexts in both a conversational and a clear style that was elicited by means of simulated recognition errors in feedback received from an interactive computer program. Acoustic measurements were taken for spectral, amplitudinal, and temporal properties known to influence fricative recognition. Results illustrate that ͑1͒ there were consistent overall style effects, several of which ͑consonant duration, spectral peak frequency, and spectral moments͒ were consistent with previous findings and a few ͑notably consonant-to-vowel intensity ratio͒ of which were not; ͑2͒ specific acoustic modifications in clear productions of fricatives were influenced by the nature of the recognition errors that prompted the productions and were consistent with efforts to emphasize potentially misperceived contrasts both within the English fricative inventory and based on feedback from the simulated listener; and ͑3͒ talkers differed widely in the types and magnitude of all modifications.

Speakers may adapt the phonetic details of their productions when they anticipate perceptual difficulty or comprehension failure on the part of a listener. Previous research suggests that a speaking style known as clear speech is more intelligible overall than casual, conversational speech for a variety of listener populations. However, it is unknown whether clear speech improves the intelligibility of fricative consonants specifically, or how its effects on fricative perception might differ depending on listener population. The primary goal of this study was to determine whether clear speech enhances fricative intelligibility for normal-hearing listeners and listeners with simulated impairment. Two experiments measured babble signal-to-noise ratio thresholds for fricative minimal pair distinctions for 14 normal-hearing listeners and 14 listeners with simulated sloping, recruiting impairment. Results indicated that clear speech helped both groups overall. However, for impaired listeners, reliable clear speech intelligibility advantages were not found for non-sibilant pairs. Correlation analyses comparing acoustic and perceptual data indicated that a shift of energy concentration toward higher frequency regions and greater source strength contributed to the clear speech effect for normal-hearing listeners. Correlations between acoustic and perceptual data were less consistent for listeners with simulated impairment, and suggested that lower-frequency information may play a role.

Research suggests that speakers can adopt a speaking style that allows them to be understood more easily when confronted with difficult communication situations, but few studies have examined the acoustic properties of clearly produced consonants in detail. This study attempts to characterize the type and magnitude of adaptations in the clear production of English fricatives in a carefully controlled range of communication situations. Ten female and ten male talkers produced nonsense syllables containing the eight English fricatives in VCV contexts, both in a conversational style and in a clear style (elicited by means of feedback consisting of simulated recognition errors received from an interactive computer program). Acoustic measurements were taken for spectral, amplitudinal, and temporal properties known to influence fricative recognition. Results illustrate that (1) there were some consistent overall clear speech effects, several of which (consonant duration, spectral peak location, spectral moments) were consistent with previous findings and a few (notably consonant-to-vowel intensity ratio) which were not; (2) ‘‘contrastive’’ differences related to eliciting prompts were observed in a few key comparisons; and (3) talkers differed widely in the types and magnitude of acoustic modifications.

The study explores

This study investigates the extent to which Japanese lexical pitch-accent distinction is neutralized in word-final position. Native speakers of Tokyo Japanese produced minimal word pairs differing in final accent status. Words were produced both in isolation and in a sentential context, where neutralization would not be expected due to following tonal specification. Examination of pitch patterns on relevant moras revealed a clear distinction between accent-opposed pairs produced in context but no such difference between items produced in isolation. Both the words produced in isolation and the words excised from sentential contexts were then presented to Japanese listeners in a lexical identification task. Participants could clearly distinguish items extracted from sentences but identified words uttered in isolation at chance level. These results suggest that phonological neutralization of final pitch accent is complete, showing no effects of underlying specification in either production or perception.