Language trade-off? No, bilingual children reliably acquire English by age 5

A new study in U.S.-born children from Spanish-speaking families finds that minority language exposure does not threaten the acquisition of English by children in the U.S. and that there is no trade-off between English and Spanish. Rather, children reliably acquire English by age 5, and their total language knowledge is greater to the degree that they also acquire Spanish. Children's level of English knowledge was independent of their level of Spanish knowledge.

source https://www.sciencedaily.com/releases/2021/06/210623091305.htm