Grammars are gaining importance in natural language processing and computational biology as a means of encoding theories and structuring algorithms. But one serious obstacle to applications of grammars is that formal language theory traditionally classifies grammars according to their weak generative capacity (what sets of strings they generate) and tends to ignore strong generative capacity (what sets of structural descriptions they generate) even though the latter is more relevant to applications.

This book develops and demonstrates a framework for carrying out rigorous comparisons of grammar formalisms in terms of their usefulness for applications, focusing on three areas of application: statistical parsing, natural language translation, and biological sequence analysis. These results should pave the way for theoretical research to pursue results that are more directed towards applications, and for practical research to explore the use of advanced grammar formalisms more easily.

Many areas of language-related research - language processing, linguistic semantics/pragmatics, speech understanding and synthesis, and psychological theories of attention - have shown an increasing need to describe and understand aspects of discourse anaphora in relation to both processing complexity and the global structure of discourse. A major problem in this area is the large gap between existing theories and accounts of actual phenomena in naturally occurring discourse. This work is an account of one aspect of discourse, local discourse structure, that makes specific claims about both processing complexity and discourse anaphora. The book focuses on Centering Theory's ability to account for data from naturally occurring discourse in several languages. The contributors test empirically several claims of Centering Theory, propose extensions to and refinements of Centering, and show how Centering can be integrated with other aspects of discourse structure and processing.