Information about talker dialect is available in high-frequency region

Abstract

Given that almost all cues to speech intelligibility are contained within the low-frequency region, high-pass filtering has not been used in speech perception research as often as low-pass filtering. We provide evidence from high-pass filtered speech that information about talker dialect is available in the high-frequency region even in the absence of intelligibility cues. Setting the upper frequency limit at 11 kHz, sentences edited out of spontaneous conversations of 20 talkers from Ohio and 20 from North Carolina were high-pass filtered with frequency cut-offs varying from 0.7 to 5.56 kHz and presented to listeners from Ohio. Results showed that listeners were still sensitive to differences between the two dialects at the two highest cut-offs, 3.32 kHz and 5.56 kHz, and dialect identification was mediated by talker sex. Also, identification of talker sex was affected by dialect, with Ohio variety providing more cues to talker sex at 3.32 kHz and the variety in North Carolina at 5.56 kHz. Speech intelligibility was reduced above 3 kHz, and Ohio speakers were more intelligible overall. Irrespective of the intelligibility loss, the results suggest that residual dialect cues are still distributed in the high frequency region, and are preserved differently in male and female voices.