Author image Igor Myroshnichenko


Lingua::EN::Semtags::Engine - extract semantic tags (semtags) from English text


  use Lingua::EN::Semtags::Engine;
  my $engine = Lingua::EN::Semtags::Engine->new;
  my @semtags = $engine->semtags("your blog post title");


Lingua::EN::Semtags uses Lingua::EN::Tagger and WordNet::QueryData to extract semantic tags (semtags) from English text. Semtags are words which reflect the semantic essence of the text (similar to topic keywords).

Lingua::EN::Semtags was designed and developed to solve a particular problem I was facing.

Problem: a user is processing blog post titles and needs to programmatically determine the posts' semantic context.

Solution: the user feeds a blog post title to Lingua::EN::Semtags and gets back a set of semtags which can be used for further processing (e.g., web searches).

Example: a blog post title like "BBtv: Graffiti Research Lab, the movie" (, Posted by Xeni Jardin, April 24, 2008 8:00 AM) would produce the following semtags: [DECORATION WORKPLACE SHOW].

Please note that the module makes the following assumptions when attempting to extract semtags:

  • only nouns, verbs, adjectives and adverbs are considered as candidate words for semtags;

  • at the time of phrase detection a frame is grown up to PHRASE_FRAME_SIZE (set to 3) tokens;

  • a language unit (a word or a phrase) is considered meaningful if its hypernym hierarchy in the WordNet database is at least MIN_ISAS (set to 3) levels deep;

  • a semtag is a meaningful language unit's hypernym at the SEMTAG_ISA_INDEX (set to 1, starts with 0) level of the hierarchy.



Calls sentence($string), gets back a populated instance of Lingua::EN::Semtags::Sentence, iterates over its Lingua::EN::Semtags::LangUnits, populates and returns an array of their semtags.


Returns an instance of Lingua::EN::Semtags::Sentence populates with Lingua::EN::Semtags::LangUnit objects which represnet meaningful language units.


Returns the Lingua::EN::Tagger instance used by the engine.


Returns/sets the verbose mode.


Returns the WordNet::QueryData instance used by the engine.


Lingua::EN::Tagger, WordNet::QueryData


Igor Myroshnichenko <>

Copyright (c) 2008, All Rights Reserved.

This software is free software and may be redistributed and/or modified under the same terms as Perl itself.