Influence of clear speech on F0 patterns of Mandarin lexical tones

Abstract

When communication becomes difficult, a talker may take on a form of communication known as clear speech (Keerstock & Smilijanic, 2019; Picheny et al., 1985). Little is known, however, about clear-speech modifications in tone languages (Zeng, 2017). This study showed how native Mandarin speakers modulate F 0 in tone words through increased variation, raised F 0 onset and offset. Participants read twenty-four sentences varied in four target tones, three times. Sentences were presented in two blocks: casual speech condition (as if talking to friends) and clear speech condition (as if communicating to someone with hearing loss). Data analysis of seven speakers suggested that effects of clear speech on F 0 contours were tone-dependent. As compared with casual speech, in clear speech, F 0 contours of high level (T1), mid-rising (T2), and high-falling (T4) tones were higher within the same tonal context; in contrast, F 0 contours of the low-dipping tone (T3) were lower preceding T1 and T4. F 0 range, onset F 0, and offset F 0 were greater in clear speech mode across most tonal environments. Additional data of eleven speakers has been collected to examine preliminary results and discuss findings in terms of signal-enhancement in clear speech production of lexical tones.