This article explores the role of usage frequency in the structure of language mixing by the application of corpus-linguistic and statistical methods. The goal of the study is to reveal that the frequency of a lexical item and the frequency with which it occurs with other items account for its use in bilingual speech. To achieve this goal, I analyze German monolingual and German-Russian mixed adjective-modified nominal constituents in otherwise Russian discourse in a corpus of Russian-German bilingual speech collected from fluent bilinguals in Russian-speaking communities in Germany. My findings show that many of German nominal constituents, also called embedded-language islands, are recurrent A-N combinations. However, in the absence of sequential associations between the involved words, the adjectives may be realized in Russian or in German. In light of this evidence, I suggest two mechanisms underlying the production of embedded-language islands: retrieval of a multiword chunk and co-activation.