Introductory Course.pdfVIP

Sabine Schulte im Walde University of Stuttgart Introduction to Corpus-based Computational Semantics: Word Senses Alexander Koller Columbia University Introductory Course ESSLLI 2007 Trinity College, Dublin, Ireland August 6-10, 2007 Word Senses Koller Schulte im Walde / ESSLLI 2007 3 Lexical Semantics and Word Senses ? Lexical semantics is the study of how and what the words of a language denote. ? Lexical semantics involves the meaning of each individual word. ? A word sense is one of the meanings of a word. ? A word is called ambiguous if it can be interpreted in more than one way, i.e., if it has multiple senses. ? Disambiguation determines a specific sense of an ambiguous word. Koller Schulte im Walde / ESSLLI 2007 4 Homonymy and Polysemy ? A homonym is a word with multiple, unrelated meanings. A homonym is a word that is spelled and pronounced the same as another but with a different meaning. bank → financial institution → slope of land alongside a river ? A polyseme is a word with multiple, related meanings. school → He goes to school every day. (institution) → The school has a blue facade. (building) → The school is on strike. (teacher) ? Regular polysemy performs a regular induction of a word sense on the basis of another, cf. school / office. Koller Schulte im Walde / ESSLLI 2007 5 Word Sense Ambiguity: Examples ? Homonymy (nouns): bank, sentence ? Homonymy (nouns vs. verbs): saw, watch, rose ? Polysemy: concrete floor vs. school floor ? Polysemy: pine cone vs. ice cream cone ? Multiple ambiguous words: time flies like an arrow Koller Schulte im Walde / ESSLLI 2007 6 Metonymy ? Metonymy is substituting a word for another word closely associated with it, or suggested by the original. ? Greek: from meta, change and onoma, name ? Examples: ? crown for king: The power of the crown was mortally weakened. ? author for his works: Im studying Shakespeare. ? noun for noun purpose (Lapata and Lascarides, 2003): Mary finished the cigarette. Koller Schulte i