When "okay" is not okay: acoustic characteristics of single-word prosody conveying reluctance.

The present study explored the acoustic characteristics of prosodic cues that indicate a speaker's reluctance when giving permission or agreement using a single word ("okay"). Eight speakers (four male, four female) produced the recorded materials that were subsequently validated through a listening experiment using 12 normal-hearing listeners. Acoustic analyses revealed that significantly longer word duration was the cue used most consistently across speakers to communicate reluctance. Voice quality, fundamental voice frequency, and intensity cues also differed significantly between the two prosodic conditions, but the manner in which these cues were applied varied greatly across speakers.