POS ( cf. part of speech tag) tagging is the short form for part of speech tagging which denotes the process of automatically assigning each word in a tokenized text a word class label from a list of part of speech tags. Part of speech tagging is implemented on the basis of principally two strategies :
rule-based part of speech tagging, a prominent example for English is the Brill tagger by Eric Brill
statistical or probabilistic part of speech tagging , most part of speech taggers today work on some kind of statistical basis. Widely used examples of statistical part of speech taggers are Helmut Schmid 's TreeTagger , the StanfordPOSTagger , and the CLAWSs tagger