World Library  
Flag as Inappropriate
Email this Article

Multiword expression

Article Id: WHEBN0014949151
Reproduction Date:

Title: Multiword expression  
Author: World Heritage Encyclopedia
Language: English
Subject: MWE, Lexicology, Lexical Markup Framework, Lexeme
Collection: Lexicology
Publisher: World Heritage Encyclopedia

Multiword expression

A multiword expression (MWE) is a lexeme made up of a sequence of two or more lexemes that has properties that are not predictable from the properties of the individual lexemes or their normal mode of combination.

For a shorter definition, MWEs can be described as "idiosyncratic interpretations that cross word boundaries (or spaces)". (Sag et al., 2002: 2).

A multiword expression can be a compound, a fragment of a sentence, or a sentence. The group of lexemes which makup up a MWE can be continuous or discontinuous. It is not always possible to mark a MWE with a part of speech.

A MWE may be more or less frozen.

Example#1 in English: to kick the bucket, which means to die rather than to hit a bucket with one's foot. In this example, that is an endocentric compound, the part of speech may be determined as being a verb. The MWE is frozen, in the sense that no variation is possible.

Example#2 in English: to throw to the lions. The pattern restricts the usage. The expression is half-frozen because a certain degree of variation is possible but everything is not possible. It is not possible for instance to say to the three lions. Like the previous example, the part of speech is a verb.

Example#3 in French: la moutarde monte au nez. This MWE is more frozen than the other examples. Let us add that a tense variation is allowed for the verb but we cannot determine what is the part of speech for the whole expression because it is a sentence.


  • Machine Translation (MT) of Multiword Expressions 1
    • Problems 1.1
    • Approaches 1.2
  • See also 2
  • References 3
  • External links 4

Machine Translation (MT) of Multiword Expressions

According to Sag et al. (2002) Multiword Expressions are, apart from Disambiguation, one of the two key problems for Natural Language Processing (NLP) and especially for machine translation (MT).

The number of MWEs in a speaker's lexicon is estimated to be of the same order of magnitude as the number of single words. Specialized domain vocabulary overwhelmingly consists of MWEs, hence, the proportion of MWEs will rise as a system adds vocabulary for new domains, because each domain adds more MWEs than simplex words.


The greatest problem for translating MWEs might be the idiomaticity problem, as many MWEs have an idiomatic sense, to a higher or a lesser degree.

For example, it is hard to predict for a system that an expression like kick the bucket has a meaning that is totally unrelated to the meaning of kick, the and bucket while appearing to conform to the grammar of English Vps. Idioms cannot be translated literally, because in many cases the idiom does not exist in an equivalent form in the target language. Attention has to be paid to syntactic and/or semantic (non)equivalence.

Also, not every MWE of the source language has a MWE in the target language as well. For example, the German MWE ins Auge fassen can only be translated by the English one-word term envisage.


The most promising approach to the challenge of translating MWEs is example based MT, because in this case each MWE can be listed as an example with its translation equivalent in the target language.

For rule based MT it would be to difficult to define rules to translate MWEs, due to the magnitude of different kinds of MWEs.

Nevertheless, an example based MT system has to apply different rules for the translation of continuous and discontinuous MWEs as it is harder to identify a discontinuous MWE in a sentence where words are inserted between the different components of one MWE.

See also


  • Dimitra Anastasiou: Idiom Treatment Experiments in Machine Translation (2010), Saarbr├╝cken.
  • Ivan A. Sag, Timothy Baldwin, Francis Bond, Ann Copestake and Dan Flickinger: Multiword Expressions: A Pain in the Neck for NLP (2002) in: LECTURE NOTES IN COMPUTER SCIENCE, Vol. 2276, pp. 1-15.

External links

  • Multiword Expression Project, at Stanford University
  • Workshops on Multiword Expressions
  • Multiword Expressions in ACL Wiki
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.