In this study1 we set out to discover what is learned by children
exposed to English morphology. To test for knowledge of morphological
rules, we use nonsense materials. We know that if the
subject can supply the correct plural ending, for instance, to a
noun we have made up, he has internalized a working system of the
plural allomorphs in English, and is able to generalize to new
cases and select the right form. If a child knows that the plural
of witch is witches, he may simply have memorized the plural
form. If, however, he tells us that the plural of *gulch is *gulches,
we have evidence that he actually knows, albeit unconsciously,
one of those rules which the descriptive linguist, too, would set
forth in his grammar. And if children do have knowledge of morphological
rules, how does this knowledge evolve? Is there a progression
from simple, regular rules to the more irregular and qualified
rules that are adequate fully to describe English? In very
general terms, we undertake to discover the psychological status of
a certain kind of linguistic description. It is evident that the
acquisition of language is more than the storing up of rehearsed
utterances, since we are all able to say what we have not practiced
and what we have never before heard. In bringing descriptive
linguistics to the study of language acquisition, we hope to gain
knowledge of the systems and patterns used by the speaker.
In order to test for children's knowledge of this sort, it was
necessary to begin with an examination of their actual vocabulary.
Accordingly, the 1000 most frequent words in the first-grader's
vocabulary were selected from Rinsland's listing. 2 This listing