A trigram tagger is a statistical part-of-speech tagger based on second order Markov model

Markov model

In probability theory, a Markov model is a stochastic model that assumes the Markov property. Generally, this assumption enables reasoning and computation with the model that would otherwise be intractable.-Introduction:...

s. It is trained on a text corpus

Text corpus

In linguistics, a corpus or text corpus is a large and structured set of texts...

 as a method to predict the next word, taking the product of the probabilities of unigram

N-gram

In the fields of computational linguistics and probability, an n-gram is a contiguous sequence of n items from a given sequence of text or speech. The items in question can be phonemes, syllables, letters, words or base pairs according to the application...

, bigram

Bigram

Bigrams or digrams are groups of two written letters, two syllables, or two words, and are very commonly used as the basis for simple statistical analysis of text. They are used in one of the most successful language models for speech recognition...

 and trigram

Trigram

Trigrams are a special case of the N-gram, where N is 3. They are often used in natural language processing for doing statistical analysis of texts.-Frequency:The 16 most common trigrams in English are:-Examples:...

. In speech recognition, algorithms utilizing trigram-tagger score better those algorithms utilizing IIMM tagger but less well than Net tagger.

The description of the trigram tagger is provided by Brants (2000).

External links

• TnT -- Statistical Part-of-Speech Tagging by Thorsten Brants