Edited in collaboration with FoLLI, the Association of Logic, Language and Information, this book inaugurates the new FoLLI LNAI subline. It constitutes the refereed proceedings of the 5th International Conference on Logical Aspects of Computational Linguistics, LACL 2005, held in Bordeaux, France in April 2005.

The 25 revised full papers presented were carefully reviewed and selected from over 40 submissions. The papers address a wide range of logical and formal methods in computational linguistics with studies of particular grammar formalisms and their computational properties, language engineering, and traditional topics about the syntax/semantics interface.

The concept of "constraint" is widely used in linguistics, computer science, and psychology. However, its implementation varies widely depending on the research domain: namely, language description, knowledge representation, cognitive modelling, and problem solving. These various uses of constraints offer complementary views on intelligent mechanisms. For example, in-depth descriptions implementing constraints are used in linguistics to filter out syntactic or discursive structures by means of dedicated description languages and constraint ranking. In computer science, the constraint programming paradigm views constraints as a whole, which can be used, for example, to build specific structures. Finally, in psycholinguistics, experiments are carried out to investigate the role of constraints within cognitive processes (both in comprehension and production), with various applications such as dialog modelling for people with disabilities. In this context, Constraints and Language builds an extended overview of the use of constraints to model and process language. This book will be useful for researchers willing to get a grip on the various uses of constraints in natural language processing, and also as a class book for academic staff who want to set up advanced courses around the concept of constraint-based natural language processing.