The role of event knowledge in early language acquisition was investig
ated. Thirteen two-year-olds were observed interacting with their moth
ers over a five-week period. During weekly observational sessions, dya
ds interacted in both a familiar-event context and an unfamiliar-event
context. Events were represented by complex toys (e.g. airport, marin
a, etc.). In the familiar-event, dyads interacted with the same event-
toy during each observation period. In the unfamiliar-event, these sam
e dyads interacted with a different novel toy during each observation
period. The results indicated that children's increasing event knowled
ge facilitated their language development. Specifically, children's le
xical type use, action verb use, and MLU increased in the familiar-eve
nt, but remained unchanged in the unfamiliar-event. Event knowledge al
so facilitated children's lexical token use. Results are discussed in
terms of the role of event knowledge in language acquisition.