A Unification-Based Model of Aspectual Type-Shifting

Coercion is an inferential process through which operator-argument conflicts are resolved in favor of the meaning of the operator, as when frame adverbials impose inchoative readings upon state-type predicates with which they are combined: The ambulance was there in a few minutes. De Swart (1998) represents such effects by means of implicit type-shifting operators that intervene between operator and argument, ensuring that the argument is of the appropriate type for the operator. This model is compositional insofar as it preserves the integrity of the functor-argument relationship, but the proposed mappings are mappings over sets of types, and as such reveal nothing about the contribution of the input lexical representation to the output representation, whether the output type is derived by coercion or by a morphosyntactically transparent type-shifting mechanism, e.g., the English Progressive. To remedy this problem, I propose that aspectual type-shifts are mappings from one Aktionsart representation to another, and that such mappings preserve input structure. This model employs two Aktionsart-based operations, permutation and concatenation, to represent both implicit and explicit aspectual type-shifts in English and French. In accordance with De Swart, I assume that coercion effects belong to linguistic interpretation, and are therefore uniformly traceable to clausal morphosyntax. For this reason, interpretations of Past and Present predications which cannot be predicted from the Aktionsart values of the entailed situation radicals, e.g., habitual, progressive, futurate and perfect readings of Present predications, are analyzed as coerced interpretations triggered by aspectual concord requirements of these tenses.