Theories of natural language syntax often characterize grammatical knowledge as a form of abstract computation. This paper argues that such a characterization is correct, and that fundamental properties of grammar can and should be understood in terms of restrictions on the complexity of possible grammatical computation, when defined in terms of…

Describes principles underlying ILLICO, a generic natural-language software tool for building larger applications for performing specific linguistic tasks such as analysis, synthesis, and guided composition. Shows to what extent this approach is relevant to the development of computer-assisted language-learning systems. (Author/VWL)