ABSTRACT
This chapter focuses on an area of comparative acquisition studies which has been extensively investigated over the last decade, and in which constant and significant progress has been made. First of all, there are adult registers of English that do not allow root null subjects, and these registers must be acquired sooner or later. One problem is that some adult systems, written registers and sometimes also oral registers, allow root null subjects, as we have seen. She assumes the following two principles to limit our system of linguistic computation: The first is more or less transparent, even though not easy to implement formally. Interpreting this state of affairs in the light of the previous discussion on the licensing of root null subjects. The chapter describes that in a standard adult system, categorial uniformity prevails over structural economy in the unmarked case, with the effect of proscribing root null subjects.
