Computational Linguistics

This book describes the theoretical underpinnings and results of Rosetta, a machine translation (MT) project that started at Philips Research Laboratory in the early 1980's; the book focuses on research carried out between 1985 and 1992. While the project was a collective enterprise among a large number of people (as the pen name indicates), the principal authors were Lisette Appelo, Theo Janssen, Franciska de Jong, and Jan Lands-bergen. The book provides a coherent distillation of dozens of publications; in particular, the work described therein has served as the basis of at least two doctoral dissertations (Janssen 1986; Appelo 1993), as well as numerous technical reports, conference papers, and journal articles. In addition to providing a novel framework for examining issues in MT, the book covers several topics that are tied together within a compositional, inter-lingual approach based on Montague grammar. Thus, it serves as a valuable resource for researchers in MT and computational linguistics; with some work it could also serve as a course textbook. 1 The main thesis of the book is that MT can be a good carrier for linguistic and computational research; thus, the emphasis is on modeling linguistic knowledge involved in the translation of natural languages (English, Dutch, and Spanish). The two main principles threaded throughout the book are: Principle of Compositionality: Two expressions are each other's translation if they are built up from parts which are each other's translation, by means of translation-equivalent rules. Principle of Isomorphism: Two sentences are considered translations of each other if they have the same semantic derivation trees (hence corresponding syntactic derivation trees). Within this framework there is a close relation between syntax and semantics: the meaning of an expression is a function of the meaning of its parts, which, in turn are deened by syntax. The translation relation corresponds to the \tuning" of grammars across language 1 For example, it might be possible to include some programming problems at the end of each chapter that would allow the student to incrementally build a mini-translation system between two languages using the principles of the Rosetta approach. An additional instructional tool would be the provision of software for use in the development of such a system.