XTAG (TAG) XTAG is an on-going project to develop a wide-coverage grammar for English using a lexicalized Tree Adjoining Grammar (TAG) formalism. XTAG also serves as an system for the development of TAGs and consists of a parser, an X-windows grammar development interface and a morphological analyzer. codesource By mcswellin Linguistics > Syntaxwith adjoininggrammarlexicalizedlinguisticssyntaxtree