This dissertation uses children’s acquisition of adjunct control as a case study

to investigate grammatical and performance accounts of language acquisition. In

previous research, children have consistently exhibited non-adultlike behavior for

sentences with adjunct control. To explain children’s behavior, several different

grammatical accounts have been proposed, but evidence for these accounts has been

inconclusive. In this dissertation, I take two approaches to account for children’s errors.

First, I spell out the predictions of previous grammatical accounts, and test these

predictions after accounting for some methodological concerns that might have

influenced children’s behavior in previous studies. While I reproduce the non-adultlike

behavior observed in previous studies, the predictions of previous grammatical

accounts are not borne out, suggesting that extragrammatical factors are needed to

explain children’s behavior.

Next, I consider the role of two different types of extragrammatical factors in

predicting children’s non-adultlike behavior. With a new task designed to address the

task demands in previous studies, children exhibit significantly higher accuracy than

with previous tasks. This suggests that children’s behavior has been influenced by task-

specific processing factors. In addition to the task, I also test the predictions of a

similarity-based interference account, which links children’s errors to the same

memory mechanisms involved in sentence processing difficulties observed in adults.

These predictions are borne out, supporting a more continuous developmental

trajectory as children’s processing mechanisms become more resistant to interference.

Finally, I consider how children’s errors might influence their acquisition of

adjunct control, given the distribution in the linguistic input. I discuss the results of a

corpus analysis, including the possibility that adjunct control could be learned from the

input. The kinds of information that could be useful to a learner become much more

limited, however, after considering the processing limitations that would interfere with

the representations available to the learner.