A varieties grammar (VG) attempts to provide a unifying apparatus for various kinds of language varieties: diatopic, diastratic, and diatypic. The notion of "family grammar" appears to be especially useful in that process since it permits the postulation of a supergrammar for the whole family as well as that of subgrammars for the individual members. In order to restrict the scope of a VG, the present approach defines varieties as typolects, which are interpreted as contrasting with idiolects. In order to make the theory of a VG applicable to pedagogical purposes the notion of a VG is further restricted to that of the grammar of a repertoire of varieties as it might exist for real speakers of English. The consideration of the needs of speakers of English as a second language leads to a redefinition of grammar in holistic terms, i.e., to an inclusion of sociocultural aspects of language into the framework of the grammar. While it is impossible to write a VG for all the varieties of English, it seems to be possible to set up ad hoc VGs of English, for instance, for English for special purposes. (Author)