How do listeners segment the continuous speech input into words? This paper adresses this important question by reviewing current views of lexical segmentation. After providing some background to more general problem of spoken word recognition, we examine the different cues - including phonetic, phonological, prosodic and lexical cues - that have been shown to play a role in sppech segmentation. We then analyse how these cues are used to locate alignment points in the continuous speech signal. These points serve to define what parts of the signal are matched with which representations in the mental lexical. Several solutions to the alignment problem are discussed in light of existing experimental evidence.