Comprehension, production, and meaning: What the regular English plural can tell us about language

The study of morphology, and more specifically the English plural, encompasses many aspects of the complexity of language, such as phonology and semantics. This thesis examines these complexities of language in a variety of studies with two-year-old-children and presents a unified description of the acquisition of the English plural. First, the long, slow, protracted course of development is documented from a six-week longitudinal study. Evidence that children know more about when the English plural applies than what they simply say is presented. To test this comprehension ability, a new test of comprehension was developed. Comprehension of singular and plural forms of real words was found to be much better than production of these same forms, evidence gained from an elicited production task. A two-week longitudinal test of comprehension and production of novel singular and plural forms reveals this difference in comprehension and production of real forms is due to frequency effects from their environment. To test potential relevant factors in children's plural productions, the importance of the meaning of the plural---the number of individuals in a set of like kinds---was tested using an elicited production task. Children were more likely to produce the plural of these well-known nouns when there were more instances and when they were identical. Spontaneous speech of parents of two-year-old children demonstrates children are not merely mimicking the input. Children's early productions, then, are not just limited by knowledge of the noun and its plural form but also by the properties of the labeled sets in ways relevant to the underlying meaning of the plural. This thesis connects the many complexities of language into a cohesive description of the progression and factors that influence children's acquisition of the English plural.