Explaining uncertainty and defectivity of inflectional paradigms

The current study investigates how native speakers of a morphologically complex language (Finnish) handle uncertainty related to linguistic forms that have gaps in their inflectional paradigms. We analyze their strategies of dealing with paradigmatic defectivity and how these strategies are motivated by subjective contemporaneousness, frequency, acceptability, and other lexical and structural characteristics of words. We administered a verb production (inflection) task with Finnish native speakers using verbs from a small non-productive inflectional type that has many paradigmatic gaps and asked participants to inflect the verbs in a given context. Inflectional uncertainty was measured by the number of different forms the participants produced for each verb. We classified produced forms that were not expected as either synonymous or novel and measured their optimal string alignment distance to expected forms. Our analyses revealed that a usage-based approach to paradigmatic defectivity fits better with the obtained results than a classical approach typically met in dictionaries and descriptive grammars. Thus, we argue, that paradigmatic defectivity can be better described as a dynamic rather than a static system, where gaps represent a continuum of possible inflectional choices rather than a lack of an inflectional variant.