On the double nature of productivity in inflectional morphology

Inflection is generally considered to be more productive than derivation. To justify such an assumption, the syntactic function of inflectional morphology is contrasted with the mainly lexical function of derivational morphology. In this paper, the whole question will be carefully discussed with the help of recently developed quantitative approaches to productivity. On the basis of data taken from Italian, it will be shown that a quantitative approach to productivity can shed light on this intricate question by revealing the double nature of inflectional morphology, which on the one hand sides with derivational morphology because of its lexically conditioned inflectional classes. On the other, it scores very high productivity rates for the single inflectional categories in accordance with its syntactic function. Furthermore, the productivity rates of the inflectional categories considered are shown to be not uniform: several factors may influence their productivity, as for instance the substitutive usage of periphrases with modals, even in a language like Italian in which the latter are far less grammaticalized than in others.