The Prosody of Backchannels in American English

We examine prosodic and contextual factors characterizing the backchannel function of single affirmative words. Data is drawn from collaborative task-oriented dialogues between speakers of Standard American English. Despite high lexical variability, backchannels are prosodically well defined: they have higher pitch and intensity and greater pitch slope than affirmative words expressing other pragmatic functions. Additionally, we identify phrase-final rising pitch as a salient trigger for backchanneling.