Predicting ineffability: Grammatical gender and noun pluralization in Icelandic

Abstract

The structure of inflectional paradigms is characterized by interdependencies between forms and categories. The question is what the nature of these interdependencies are and how they are discovered in acquisition. In this article, I approach these issues from a learning perspective using gender and plural formation in Icelandic as a case study. Specifically, I investigate how knowledge of grammatical gender facilitates the induction of plural forms or vice versa. Noun pluralization in Icelandic cross-cuts both gender and inflection classes, raising the question of how children can extract the relevant generalizations given syncretism both within and across inflectional paradigms. In a corpus study, I show how predictions regarding the productivity of correspondences between gender and plural forms in Icelandic can be formulated by the Tolerance Principle, a learning model proposed by Yang (2005; 2016). The model centers around a threshold function that predicts the division line between productive and unproductive linguistic patterns in language based on the proportion of exceptions associated with any given pattern. These predictions were put to the test in two elicited production studies on both children and adults. I demonstrate how both children and adults were at a loss to pluralize nouns that they were unable to assign gender to. Thus, productivity in gender assignment correlated with productivity in plural formation. Since knowledge of gender is contingent on the knowledge of productive nominative singular forms, I propose that gender may be a developmental prerequisite for the acquisition of plural formation in Icelandic due to the statistical primacy of singular forms in the input. I argue that gaps within the inflectional paradigm of Icelandic nouns follow naturally from a learning process guided by productivity that fails and results in rote memorization.