Lexical substitution
Encyclopedia
Lexical substitution is the task of identifying a substitute for a word
in the context of a sentence
. For instance, given the following sentence: "After the match, replace any remaining fluid deficit to prevent chronic dehydration throughout the tournament", a substitute of game might be given.
Lexical substitution is strictly related to Word Sense Disambiguation
(WSD), in that both aim to determine the meaning
of a word. However, while WSD consists of automatically assigning the appropriate sense
from a fixed sense inventory, lexical substitution does not impose any constraint on which substitute to choose as the best representative for the word in context. By not prescribing the inventory, lexical substitution overcomes the issue of the granularity of sense distinctions and provides a level playing field for automatic systems that automatically acquire word senses (a task referred to as Word Sense Induction
).
in 2007. A Semeval-2010 task on cross-lingual lexical substitution has also taken place.
Word
In language, a word is the smallest free form that may be uttered in isolation with semantic or pragmatic content . This contrasts with a morpheme, which is the smallest unit of meaning but will not necessarily stand on its own...
in the context of a sentence
Sentence (linguistics)
In the field of linguistics, a sentence is an expression in natural language, and often defined to indicate a grammatical unit consisting of one or more words that generally bear minimal syntactic relation to the words that precede or follow it...
. For instance, given the following sentence: "After the match, replace any remaining fluid deficit to prevent chronic dehydration throughout the tournament", a substitute of game might be given.
Lexical substitution is strictly related to Word Sense Disambiguation
Word sense disambiguation
In computational linguistics, word-sense disambiguation is an open problem of natural language processing, which governs the process of identifying which sense of a word is used in a sentence, when the word has multiple meanings...
(WSD), in that both aim to determine the meaning
Meaning (linguistics)
In linguistics, meaning is what is expressed by the writer or speaker, and what is conveyed to the reader or listener, provided that they talk about the same thing . In other words if the object and the name of the object and the concepts in their head are the same...
of a word. However, while WSD consists of automatically assigning the appropriate sense
Word sense
In linguistics, a word sense is one of the meanings of a word.For example a dictionary may have over 50 different meanings of the word , each of these having a different meaning based on the context of the word usage in a sentence...
from a fixed sense inventory, lexical substitution does not impose any constraint on which substitute to choose as the best representative for the word in context. By not prescribing the inventory, lexical substitution overcomes the issue of the granularity of sense distinctions and provides a level playing field for automatic systems that automatically acquire word senses (a task referred to as Word Sense Induction
Word sense induction
In computational linguistics, word-sense induction or discrimination is an open problem of natural language processing, which concerns the automatic identification of the senses of a word...
).
Evaluation
In order to evaluate automatic systems on lexical substitution, a task was organized at the Semeval-2007 evaluation competition held in PraguePrague
Prague is the capital and largest city of the Czech Republic. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of over 2.3 million...
in 2007. A Semeval-2010 task on cross-lingual lexical substitution has also taken place.
See also
- Word Sense DisambiguationWord sense disambiguationIn computational linguistics, word-sense disambiguation is an open problem of natural language processing, which governs the process of identifying which sense of a word is used in a sentence, when the word has multiple meanings...
- Word senseWord senseIn linguistics, a word sense is one of the meanings of a word.For example a dictionary may have over 50 different meanings of the word , each of these having a different meaning based on the context of the word usage in a sentence...
- Lexical semanticsLexical semanticsLexical semantics is a subfield of linguistic semantics. It is the study of how and what the words of a language denote . Words may either be taken to denote things in the world, or concepts, depending on the particular approach to lexical semantics.The units of meaning in lexical semantics are...
- SemEvalSemEvalSemEval is an ongoing series of evaluations of computational semantic analysis systems; it evolved from the Senseval word sense evaluation series. The evaluations are intended to explore the nature of meaning in language...