Research on clear speech, an intelligibility-enhancing speaking style, has proposed that global clear speech modifications which make speech more perceptible in adverse conditions are language-independent, while the more fine-grained segmental clear speech modifications, which enhance the salience of phonological contrasts, are language-specific [Bradlow, A.R. & Bent, T., 2002. The clear speech effect for non-native listeners. Journal of the Acoustical Society of America, 112, 272–284]. This study assessed the claim by contrasting the clear speech strategies used by twelve Finnish-English late bilinguals in their two languages, using spontaneous speech and sentence reading tasks. Their global clear speech modifications were also compared to those of native English speakers. Global measures included mean energy between 1-3k Hz, f0 median and range, and speech rate, while segmental measures included VOT for initial stop consonants and vowel spectral and temporal characteristics for two vowel contrasts. The global clear speech strategies of late bilinguals approximated those of native English speakers. Findings generally support the hypothesis that global enhancements are language-independent while segmental enhancements are language-dependent: the late bilinguals enhanced some of the segmental detail differently in clear speech according to the language being spoken, but most of the global clear speech modifications were consistent across languages
