Pragmatic ambiguity: the thetic function of modality

The aim of this paper is to present an overview of the pragmatic aspects of ambiguity present in deontic sentences, which may have three pragmatic functions: a prescriptive or a descriptive or a constitutive function. This type of ambiguity is investigated on the lexical, phrasal, and sentential level. The discussion focuses on the deontic constructions of the German verb sollen and the English shall as they are used in legal texts. It also includes comments on the thetic function of the Latin imperative mood and the subjunctive mood.