This study assesses the determinants of English‐language proficiency among three subgroups of Israeli immigrants in the United States, namely native‐born Israeli Jews, foreign‐born Israeli Jews, and Palestinian Arabs, and how these determinants have changed over time. Multivariate analyses of decennial censuses from 1980, 1990, and 2000 reveal substantial differences in the directions and significance of the relationships between the independent variables and English proficiency of the subgroups under investigation. Ethnoreligious affiliation per se is seen to be an important factor that consistently explains intra‐group variation in English proficiency. This lends support to the split approach over the lump approach in attempting to understand immigrants' linguistic dynamics in the new country. The findings are discussed in reference to three working hypotheses – “exposure,” “efficiency,” and “economic incentives” – and in the specific sociopolitical conditions of Jews and Arabs at both origin and destination.