Prosodic generalizations in the Brazilian Portuguese diphthongal plural

The diphthongal plural in Brazilian Portuguese is sensitive to three phonological factors: monosyllabicity, licensing of nasal diphthongs by stress, and vertical dispersion of oral diphthongs. We present an analysis that captures the gradient distribution of the Brazilian Portuguese plurals ending in diphthongs, both oral and nasal, using a probabilistic grammar based on the well-understood factors mentioned above. This grammar is trained on corpus data and is sensitive to prosodic generalizations; it correctly derives existing plurals while accurately generalizing beyond individual lexical items and predicting participants’ choices in nonce word tasks. The results are incompatible with analyses that apply uniformly to all lexical items, as well as with those that simply memorize semipredictable plurals without incorporating phonologically-based generalizations.