The goal of the project is to establish new theories of language internal conditions for grammatical change over time. This will be done on the basis of empirical data from a variety of languages, and recent linguistic theory. The project will concentrate on identifying principles and mechanisms which underlie grammatical change. In all languages we can observe change over time. Such changes may have identifiable external causes, but those usually explain only why a process of change started at some point. In order to explain why the outcome of the change is as it is we need theories of grammar and internal linguistic structure. This project will deal with the relationship between internal linguistic structure and grammatical change. The relationship between language acquisition and change has become a hot topic in modern linguistics, and precise hypotheses have been formulated about how the grammar of a language may change in the process of first language acquisition. In a project like this, material from various languages and language families are of crucial importance. The participants include experts on older Germanic languages, Slavic languages, Latin and Romance, Finno-Ugric languages, Caucasian languages, and native American Languages. Some of the participants work within various versions of formal generative grammar, others have their theoretical basis on more functional and typological theories.