How kids learn to say the darnedest things: the effect of multiple exemplar instruction on the emergence of novel verb usage.

We report experiments using time-lagged pre- and postintervention designs with (a) 4 first graders with learning delays, and (b) a systematic replication with 3 preschoolers with learning delays. Both experiments tested the effects of multiple exemplar instructional procedures (MEI) on the emergence of untaught past tense emission of novel regular verbs (e.g., jumped derived from jump) and grammatically inaccurate but experimentally correct usage of irregular verbs (e.g., singed derived from sing). Prior to the MEI, none of the children could produce regular or irregular past tense forms to pictures that provided simulated contexts (pictures with backgrounds for past and present tense). MEI provided across the picture contexts for past and present tense used separate training sets of verbs to teach children to form regular past tense. After either 1 or 2 MEI training sets, the children emitted accurate past tense forms of the untaught regular and inaccurate, but experimentally correct irregular verbs. These findings provided an instructional history that resulted in the children's acquisition of past tense for untaught regular past tense verbs and "creative" errors with irregular tenses. Results are discussed in terms of the research on experimentally induced sources for novel verbal behavior and related interpretations.