Difference between revisions of "Tagger"

From Glottopedia
Jump to navigation Jump to search
Line 12: Line 12:
  
 
==Subtypes==
 
==Subtypes==
 +
* [[Brill tagger]]
 
* [[HMM tagger]]
 
* [[HMM tagger]]
* [[Brill tagger]]
 
 
* [[Memory-based tagger]]
 
* [[Memory-based tagger]]
 
* [[Tree tagger]]
 
* [[Tree tagger]]

Revision as of 17:55, 6 July 2007

Definition

A tagger is a device which assigns symbolic labels (tags) to linguistics units. The labels are taken from a predefined set of symbols (tag-set).

Comments

In most cases, a tagger assigns tags representing morpho-syntactic information to single word-forms or token. But there are tagger which have been designed to identify semantic role of noun phrases or prepositional phrases (sense tagging) and sometimes identiying the discourse structure of a text is considered as a king of tagging.

Conceptually, tagging can be considered as a three step process: (i). identification of the relevant units (ii). assigning all possible labels to the units (e.g. by lexical look-up, applying heuristics, etc.) (iii). disambiguation.

It is common practice to distinguish between rule-based and stochastic tagger, though some tagger combine rules and stochastic information.

State-of-the-art tagger achieve a precision of at least 95% for morpho-syntactic tagging.

Subtypes

Other Languages