I argue that because of spelling and typing errors and other properties of typed text, the identification of words and word boundaries in general requires syntactic and semantic knowledge. A lattice representation is therefore appropriate for lexical analysis. I show how the use of such a representation in the CLARE system allows different kinds of hypothesis about word identity to be integrated in a uniform framework. I then describe a quantitative evaluation of CLARE's performance on a set of sentences into which typographic errors have been introduced. .