This study investigated experimentally the nature and development of c
hildren's early productivity with nouns, both in verb-argument structu
re and with plural morphology. Eight 20- to 26-month-old boys and girl
s were, in the context of playing a game over a several week period, e
xposed to four novel nouns, modeled in experimentally controlled ways.
The question was whether, when, and in what ways the children would b
ecome productive with these nouns in their spontaneous speech, going b
eyond the particular linguistic forms they had heard. In terms of verb
-argument structure, 7 of the 8 children used their nouns in productiv
e argument roles, that is, in semantic roles they had not heard them u
sed in. Five of the 8 children used the plural morpheme productively w
ith the novel nouns as well. Implications for theories of grammatical
category formation are discussed.