Level-ordering in lexical development

This paper examines the claim that lexical word formation rules are ordered at three levels of application (Kiparsky, 1982). Lexical rules of affixation and compounding differ with respect to phonological effects, semantic regularity and productivity. With respect to these properties, rules can be assigned to one of three “levels” and are applied sequentially. Level-ordering predicts that irregular plurals may be formed at level 1 prior to compounding at level 2. Thus, forms such as mice-infested are acceptable. However, regular plurals formed at level 3 may not precede compounding, therefore predicting that ¹rats-infested is not acceptable. A learnability problem arises since the child almost never hears compounds containing irregular plurals. Given that the input appears to underdetermine the relevant constraints, it is suggested that level-ordering is an innate structural property of the lexicon. It is predicted that children should show no evidence of having to learn the constraints of level-ordering with respect to pluralization and compounding. An experiment with 33 three- to five-year-olds elicited singular, plural and compound forms of regular, irregular and pluralia tantum nouns (also at level 1). Results showed that: (1) Children almost never produced regular plurals inside compounds (e.g., ¹rats-eater); (2) As soon as children used irregular plurals, they used them inside compounds (e.g., mice-eater); (3) Pluralia tantum nouns were also used inside compounds (e.g., clothes-eater) although for various phonological and semantic reasons there appeared to be a difference for the individual nouns within this class. The results strongly support the notion that level-ordering constrains the child's word formation rules, independent of the input received. Some possible mechanisms for assigning rules to their appropriate levels are discussed.