Preschoolers’ developing comprehension of the plural: the effects of number and allomorphic variation

Previous intermodal preferential looking (IPL) studies have found that children learning English acquire knowledge of plural allomorphs incrementally. The segmental plural /-s/ (e.g., cats) is understood at 24 months of age, whereas the syllabic plural /-əz/ (e.g., buses) is not comprehended until 36 months. Production studies also show ongoing challenges with the syllabic plural /-əz/, suggesting a prolonged weaker representation for this allomorph. IPL studies also suggest that children do not understand the singular, which has no overt marking, until 36 months of age. However, the status of children's developing representations of the singular has been largely unstudied. The current study, therefore explored 116 3- and 4-year-olds’ developing comprehension of novel singular and plural words, where the plurals were inflected with segmental and syllabic plural allomorphs. Results found that children were equally proficient at identifying novel plurals of both allomorph types, increasing accuracy with age. However, children's accuracy with novel singulars did not increase with age, raising questions about the representation of null morphology. Children's equal accuracy across plural allomorphs is more consistent with rule-based models of morphological representation than those proposing morphology as an emergent property of the lexicon. However, neither model completely accounts for the developmental differences found between singular and plural.