This paper examines two crucial aspects of the assimilation experience of ethnic minority immigrants in the United Kingdom. It explores the determinants of their English language (speaking) fluency and the key role such skills play in their occupational success. Our sample is derived from the Fourth National Survey of Ethnic Minorities undertaken in 1994. Uniquely this data contains an interviewer-assessed measure of English language fluency. Importantly, we also attempt to control for possible endogeneity bias in the estimates of the effect of language fluency on occupational success. We find that fluency is associated with significantly higher mean hourly occupational wages.