Graph Grammar Approach to Natural Language Parsing and Understanding

Abstract

String grammars have been found in many ways inadequate for parsing inflectional languages with "free" word order . 'I'o overcome theseproblems we have replaced linear string gramma rs and tree transformations by their multidimensional ~neralization , graph gramma rs. In our approach parsing i.s seen as a ~ransformation between two graph languages , namely the sets of QOrphological and semantic representations of natural language sentences . An experimental Finnish question - answering system SUVI based on graph grammars has been implemented. In SUVI the role of individual words is active . Each word is associated to a syntactico-seuanoic constituent type that is representeda transition networklike graph whose transitions correspond to transformations in the derivation graph. Parsing is performed by interpreting the constituent type graphs corresponding to the words of the current sentence.