Two experiments involving plural and past tense inflection in Dutch offer support for exemplar
models of inflectional morphology and question the need for a default process in these
inflection systems. In a first experiment we asked participants in two age-groups (35- or-
younger and 55-or-older) to make forced choices between plural forms of stems that can take the
two productive and regular Dutch plural suffixes (-en and -s). Results showed that the relative
frequencies of these two plural forms in a corpus were highly predictive for the plural choice.
We also found a significant effect of age, the younger group having a consistently higher
preference for the -s plural. We conclude that -s plurals are becoming more frequent in Dutch,
and that, as a result, both age-groups have different relative frequencies for double plural
forms. We suggest that single- mechanism exemplar models can naturally explain the age effect
and speakers' sensitivity to the relative frequencies of two acceptable regular plurals ,
while dual-mechanism models could only explain it by assuming full storage for both forms,
which would be incompatible with the proposal that both -en and -s plural inflection are
default processes (Pinker, 1999). In a second experiment, a replication of Prasada & Pinker
(1993, experiment 2), we collected acceptability ratings for regular and irregular past tense
forms of pseudowords. We obtained results similar to Prasada & Pinker: irregular past tense
forms were rated less acceptable as their phonological similarity to existing irregulars
decreased, ratings for regulars were less affected by phonological similarity. However,
contrary to the previous authors' conclusion that a default process is required to explain
these results, we offer an explanation in which ratings are not only based on phonological
similarity but also on lexical characteristics such as neighbourhood density, which
differentiate regular and irregular Dutch verbs (e.g. Tabak, Schreuder, & Baayen, 2005). We
demonstrate how an exemplar-based model can make use of these lexical characteristics to
explain the data of the rating experiment.
References
Pinker, S. (1999). Words and Rules. London: Phoenix.
Prasada, S., & Pinker, S. (1993). Generalizations of Regular and Irregular Morphological
Patterns. Language and Cognitive Processes, 8, 1-56.
Tabak, W., Schreuder, R., & Baayen, R. H. (2005). Lexical statistics and lexical
processing: semantic density, information complexity, sex and irregularity in Dutch. In S.
Kepser & M. Reis (Eds.), Linguistic Evidence Computational Perspectives. Berlin:
Mouton de Gruyter.