ABSTRACT
Syntactic theory circumscribes syntactic variation and thus syntactic change: potential changes are, in the first place, either impossible, as infringing universals of syntax, or possible. Many recurrent changes involve minimal incremental or decremental modification, such that the change involves a local increase or decrease in what is allowed within the syntax of a particular language, where locality is defined by syntactic theory. Notional grammar provides for each language a set of notionally defined categories out of which syntactic representations are built in accordance with particular parameter settings appropriate to that language. This chapter discusses the notional definitions of the features and the motivations for attributing particular combinations to particular categories; the role of the representations in providing appropriately for cross-classification; markedness; and hierarchization. Uses of some of the prototypical modals have for some time shown the notional characteristics that one might associate with a syntactic class of modal.
