Lexical analysis is also an important early stage in natural language processing, where text or sound waves are segmented into words and other units. This requires a variety of decisions which are not fully standardized, and the number of tokens systems produce varies for strings like "1/2", "chair's", "can't", "and/or", "1/1/2010", "2x4", "...,", and many others. This is in contrast to lexical analysis for programming and similar languages where exact rules are commonly defined and known.
