This volume presents principles and models for describing language variation, and introduces a time-based, dynamic framework for linguistic description. The book first summarizes some of the problems of grammatical description encountered from Saussure through the present and then outlines possibilities for new descriptions of language which take into account sociolinguistic factors. For instance, a static framework would view creole situations as "freak" situations and creoles as necessarily unstable and rapidly changing. A dynamic framework would endorse the Saussurian paradox that competence is looked for exclusively in the individual, but variety is sought in society. A dynamic framework would hold that competence is polylectal; what language-users know about communicating with others more nearly represents their language competence than the subset of this knowledge exhibited in production. The bulk of the text centers around the enumeration of principles and the presentation of models for variation theory. A paper on feature marking and weighting is appended. (CAL/DB)