Language assimilation and performance in achievement tests among Hispanic children in the U.S.: Evidence from a field experiment

We provide new evidence about the effect of testing language on test scores using data from two rounds (conducted approximately six years apart) of the New Immigrants Survey. In each round, U.S.-born and foreign-born children of Hispanic origin were randomly assigned to take the Woodcock-Johnson achievement (two reading and two math) tests, either in Spanish or in English. U.S.-born children of Hispanic immigrants perform better in reading tests (but not in math tests) when they are assigned to take tests in English. The size of the testing-language effect remains stable across rounds. Foreign-born children of Hispanic immigrants perform better in both reading and math tests when they are assigned to take tests in Spanish in the first round. However, the size of the testing-language effect declines in reading tests and completely disappears in math tests by the second round. Our results suggest that the depreciation of Spanish skills is an essential factor (and, in some cases, more important than the accumulation of English skills) in explaining the decline in the testing-language effect among foreign-born children. We also explore how age at immigration and years spent in the U.S. affect language assimilation.