An understanding of cross-language effects in semantic and morphosyntactic abilities is an important pre-requisite to the successful acquisition of English as a second language in school-age children of all ages. Unlike monolingual English-speaking students, language-minority students bring abilities that are linked to their first language—both its oral and written forms. Studies on cross-language/modal effects show in what ways the additional linguistic resources of language-minority students influence their language development in English. Taking first-language influences into account does not necessitate teaching in the first language. Rather, it means, incorporating first-language effects in our understanding of the progress of language-minority students in school, when seeking to identify the sources of difficulty individual students may have in mastering English as a second language, and when devising educational curricula that are relevant and appropriate to language-minority students even if their education is entirely through the medium of English.