This paper reviews what is currently known about the sensory and perceptual input that is made available to the word recognition system by processes typically assumed to be related to speech sound perception. In the first section, we discuss several of the major problems that speech researchers have tried to deal with over the last thirty years. In the second section, we consider one attempt to conceptualize the speech perception process within a theoretical framework that equates processing stages with levels of linguistic analysis. This framework assumes that speech is processed through a series of analytic stages ranging from peripheral auditory processing, acoustic-phonetic and phonological analysis, to word recognition and lexical access. Finally, in the last section, we consider several recent approaches to spoken word recognition and lexical access. We examine a number of claims surrounding the nature of the bottom-up input assumed by these models, postulated perceptual units, and the interaction of different knowledge sources in auditory word recognition. An additional goal of this paper was to establish the need to employ segmental representations in spoken word recognition.