This research focuses on patterns of English proficiency and use-of-English among older immigrants living in linguistically concentrated, ethnic neighborhoods. A sample (n=60) of older Puerto Ricans, who moved from the island to the mainland in their twenties, were divided into English proficiency groups (fluent, high intermediate, low intermediate) via the Adult Language Assessment Scales. Participants then provided self-ratings of their English proficiency (understanding, speaking, reading, and writing), their use of English in social domains (language spoken with own-family, in-laws, spouse, children, neighbors, and workmates), and their use of English in private psychological domains (language of talking to oneself, counting, writing notes to oneself, thinking, dreaming, praying, and expressing feelings). Finally, all participants completed the Puerto Rican Bicultural Scale. Results show a cohort of immigrant elders whose first language is protected by their ethnic neighborhoods but whose domestic and private lives are increasingly permeated by English. In particular, children emerge as powerful forces of language socialization in English for their parents. Further, there are important individual differences by level of proficiency, with a lowest proficiency group that is less acculturated, lower in socioeconomic status, and even more linguistically isolated than groups with higher proficiency. In essence, level of second language proficiency is a potent source of intracultural variation. Methodologically, the paper makes the important point that self-rated patterns of language use are consistent with scores on formal measures of proficiency. The paper also provides empirical verification of the logic of dividing language use into external, social speech and internal, psychological speech.