The insertion of the English connective so and similar items into Spanish discourse of bilingual speakers in the United States does not fit easily into accepted typologies of code-switching and borrowing. Such insertions are found among fluent bilinguals, among English speakers who have learned Spanish as a second language, and among Spanish-speaking immigrants to the United States who have learned English as a second language. Insertion of so is typically done unconsciously and often passes unnoticed. This paper offers an analysis combining the variable status of inserted so as code-switch or congruent lexicalization and the sociolinguistic configurations that result in metalinguistic "bracketing" of Spanish discourse by English across a broad spectrum of speakers.