The effect of speech rate on the distinction between "slit" and "split" was investigated. This distinction may be cued solely by a silent interval (SI) of sufficient duration between the [s] and the , and the boundary SI, at which "slit" and "plit" are perceived with equal probability, determined. In this experiment, although subjects showed good identification of the stimulus categories within the range of silent intervals used, no shift in the boundary SI was found for a twofold increase in speech rate. This finding is contrasted with most recent experiments which demonstrate "compensation" for changes in speaker characteristics, such as speech rate. Implications for models of speech perception are discussed.