The pending Immigration Reform and Control Act (Simpson‐Mazzoli) would require current illegal aliens to demonstrate minimal proficiency in English or to enroll in an English language class to attain permanent‐resident status. This paper examines the importance of English language skills in the assimilation of immigrants. Data on 1975 earnings for men from 11 language /ethnic groups are used. English skills are found to play an important role in determining the earnings of immigrant and minority‐language men in the U.S. Costs of deficiencies in English are substantial for most immigrants—more than $1,000 per year for eight of the 11