The maintenance of clear speech in naturalistic conversations.

Clear speech is a style that speakers adopt when talking with listeners whom these speakers anticipate may have a problem understanding speech. This study examines whether native English speakers use clear speech in conversations with non-native English speakers when native speakers are not explicitly asked to use clear speech (i.e., clear speech elicited with naturalistic methods). The results of the study suggest that native English speakers use clear speech in conversations with non-native English speakers even when native speakers are not explicitly asked to. Native English speakers' speech is more intelligible in the early portions of the conversations than in the late portions of each conversation. Further, the speakers "reset" to clearer speech at the start of each Diapix picture. Additionally, acoustic properties of the speech are examined to complement the intelligibility results. These findings suggest the instigation of clear speech may be listener-driven but the maintenance of clear speech is likely more speaker-driven.