The major objective of the proposed research is to identify some of the talker and listener characteristics that contribute to variation in speech intelligibility. The study consists of an extensive examination of the production and perception of """"""""clear speech,"""""""" a distinct speaking style that talkers adopt when the listener has speech perception difficulties due to a hearing loss, background noise, or a different native language. To the extent that clear speech is more intelligible than """"""""conversational speech,"""""""" an acoustic-phonetic comparison of these two speaking styles provides unique information about factors that affect speech intelligibility. The proposed studies will test the hypothesis that naturally produced clear speech reflects an interaction of universal, auditory-perceptual factors, which serve to enhance the overall acoustic salience of the speech signal such that it is more resistant to the adverse effects of environmental noise or listener-related perceptual deficits, and 1anguage-specific structural factors, which serve t o e enhance t he realization of phonologically important contrasts. Two important predictions of this hypothesis are (a) clear speech production will show predictable and systematic similarities and differences across languages, and (b) the intelligibility benefit of naturally produced clear speech will be greater for listeners with well-entrenched knowledge of the sound structure of the target language than for listeners with limited experience with the sound structure of the target language. In order to test these predictions two projects are proposed. Project 1 will investigate variability in clear speech production by comparing the conversational-to-clear speech transformations in English and Spanish. Project 2 will investigate variability in clear speech perception by comparing the clear speech intelligibility benefit across listeners that vary with respect to their experience with the sound structure of the target language (native vs. non-native listeners, adults vs. children).

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Language and Communication Study Section (LCOM)
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Shekim, Lana O
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Northwestern University at Chicago
Schools of Arts and Sciences
United States
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Cooper, Angela; Bradlow, Ann (2018) Training-induced pattern-specific phonetic adjustments by first and second language listeners. J Phon 68:32-49
Vaughn, Charlotte R; Bradlow, Ann R (2017) Processing Relationships Between Language-Being-Spoken and Other Speech Dimensions in Monolingual and Bilingual Listeners. Lang Speech 60:530-561
Bradlow, Ann R; Kim, Midam; Blasingame, Michael (2017) Language-independent talker-specificity in first-language and second-language speech production by bilingual talkers: L1 speaking rate predicts L2 speaking rate. J Acoust Soc Am 141:886
Brouwer, Susanne; Bradlow, Ann R (2016) The Temporal Dynamics of Spoken Word Recognition in Adverse Listening Conditions. J Psycholinguist Res 45:1151-60
Cooper, Angela; Bradlow, Ann R (2016) Linguistically guided adaptation to foreign-accented speech. J Acoust Soc Am 140:EL378
Wright, Beverly A; Baese-Berk, Melissa M; Marrone, Nicole et al. (2015) Enhancing speech learning by combining task practice with periods of stimulus exposure without practice. J Acoust Soc Am 138:928-37
Cooper, Angela; Brouwer, Susanne; Bradlow, Ann R (2015) Interdependent processing and encoding of speech and concurrent background noise. Atten Percept Psychophys 77:1342-57
Calandruccio, Lauren; Bradlow, Ann R; Dhar, Sumitrajit (2014) Speech-on-speech masking with variable access to the linguistic content of the masker speech for native and nonnative english speakers. J Am Acad Audiol 25:355-66
Burchfield, L Ann; Bradlow, Ann R (2014) Syllabic reduction in Mandarin and English speech. J Acoust Soc Am 135:EL270-6
Brouwer, Susanne; Bradlow, Ann R (2014) Contextual variability during speech-in-speech recognition. J Acoust Soc Am 136:EL26-32

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