A POS (part of speach) tagger is used as an early stage in natural language processing. The POS tagger takes text as input and attaches to each word (or sometimes group of words) a tag representing what part of speach it is being used in. Note the same word may be used in differet ways in different sentances, for example, 'going' is a verb in "I am going to the shops", but a noun in "his going will be rued". This can sometimes help in disambiguating synonyms, such as 'bow' the action (typically used as a verb) vs the weapon (used as a noun). However, this does not solve all ambiguity, for example the difference between 'bow' the weapon and back of a ship requires semantic disambiguation. Typically POS tagger is followed by higher levels of parsing to create a grammar tree or other representation, but it may be used on its own in simple applications.
Used on pages 305, 312, 313
Also known as pos tagging