Abstract
This study assesses the role of frequency of input in the acquisition of the present perfect by Scottish and American children. Two questions were addressed: (1) Do adults speaking Scottish English use the present perfect more frequently in speech to children than those speaking American English? (2) If there is a difference in the frequency of input, how does this affect the course of development of this structure in the language of Scottish vs. American children? Cross-sectional data were collected from 12 Scottish and 12 American children aged 3; 0 to 6; 4 and from adults interacting with them in naturalistic settings. The data led to the conclusions that (1) Scottish adults use the present perfect construction in their speech to children much more frequently than American adults do; (2) Scottish children use the present perfect construction in their speech long before their American counterparts; and (3) frequency of input does play a major role in the timing and order of acquisition of the present perfect. However, its role appears to be an interactive one, in which it conspires with factors such as semantic, syntactic, and cognitive simplicity to make some forms easier to learn than others.