Proceedings of the Annual Meeting of the Cognitive Science Society

Connectionist accounts of inflectional morphology have focussed on the domain of the English Past Tense (e.g. Rumelhart & McClelland 1986; Plunkett & Marchman 1993). In this inflectional domain, the default mapping process (add /ed/) reflecLs the process of suffixation adopted by the majority of the forms in the language. Connectionist models exploit the imbalance between EngHsh regular and irregular verbs when learning the past tense and when responding to novel forms in a default fashion. Not all inflectional systems have a default mapping which is characterized by a majority of forms in the language. The Arabic Plural System has been cited (Marcus et al. 1993) as one such system where a minority default mapping process operates. The Sound Plural in Arabic applies to only a minority of forms in the lexicon (~104;), yet it appears to adopt the role of a default mapping for novel nouns. W e describe a connectionist model that can learn a minority default mapping analogous to the Arabic plural and discuss its performance in relation to type and token frequency effects, and their distribution within phonetic space.