Age of acquisition and ultimate performance. The first question they asked was whether there was a relation between age of acquisition and ultimate performance in the grammar of a second language. The results of this study clearly show such a relation, and therefore support the notion that children have an advantage over adults in acquiring a second language. The overall correlation between age of arrival in the United States and performance on the test of English grammar was -.77; and for those subjects arriving in the United states before puberty, this correlation was -.87.