The MacArthur-Bates Communicative Development Inventories (CDIs) are a widely used family of parent-report instruments for easy and inexpensive data-gathering about early language acquisition. CDI data have been used to explore a variety of theoretically important topics, but, with few exceptions, researchers have had to rely on data collected in…

Six lexical principles for object label learning are evaluated. In this framework, lexical acquisition changes as a result of the particular principles a given child has at his or her disposal. These principles were developed for the class of object labels but may also apply across other early-appearing word classes. (Contains 98 references.) (JP)

Type/Token Ratios (TTRs) frequently fail to discriminate between children at widely different stages of language development, and may fall as children get older. Such effects are caused by a negative, though non-linear, relationship between sample size and TTR. Standardization of the number of tokens before computing TTRs is recommended.…