Rate-dependent speech processing can be speech-specific: Evidence from the disappearance of words under changes in context speech rate

Function words in casual speech can be made to disappear by slowing the surrounding speech rate [1]. The current study explored the domain generality of this disappearing word effect, asking whether function words can be made to disappear by manipulating temporal properties of nonspeech context. Stimuli were short word sequences (e.g., minor or child) appended to precursors that were either speech, low-pass filtered speech, or tone sequences, presented at a spoken rate and a slowed rate. Across two experiments, only precursors heard as intelligible speech generated a speech-rate effect (i.e., reporting fewer function words in a slowed vs. normal-rate context), suggesting that rate-dependent speech processing can be domain-specific.