Code-switching or Borrowing? No sé so no puedo decir, you know

In the study of bilingual code-switching, identifying the typology and language of individual switched elements has generally proceeded from theoretical models involving the identification of a base language and the phrase structure of both languages. Such fundamental notions as word order, the language of functional heads, relations of syntactic government, and purely quantitative measures of the amount of material in each language have variously been used to classify language switching within a single clause. The formal study of bilingual code-switching—with Spanish-English bilingualism receiving high prominence—has enjoyed more than three decades of serious activity, incorporating the intersection of sociolinguistics and variationist models, syntactic theory, psycholinguistics, neurolinguistics, and literary and cultural studies. After more than three decades of research on Spanish-English code-switching it might seem that there is little left to explore; there are, however, some phenomena that do not fit easily into current typologies, and one such manifestation will be explored in the present study. An accepted axiom of Spanish-English code-switching is that there are clear quantitative and qualitative differences among the language switches of fluent bilinguals, Spanish-speaking immigrants who learned English in adolescence or adulthood, and native speakers of English who have acquired Spanish as a L2. The first group is most noted for intrasentential code-switching and for the use of language switches to achieve pragmatic ends such as foregrounding, ethnic solidarity, persuasion, and the like. Calques of idiomatic expressions in English are frequent when speaking Spanish, with fewer cases of Spanish calques in English discourse, and numerous loans from English are present. Spanishspeaking immigrants typically switch only at major discourse boundaries such as sentences and paragraphs, usually in response to shifting domains of discourse. Calques from English are rare and English lexical items are usually inserted in non-assimilated fashion. English-speaking students of Spanish switch to English primarily when their abilities in Spanish are exceeded by the demands of a particular communicative task, and often show less sensitivity to the linguistic abilities and preferences of their interlocutors. Calques from English are common, including combinations that violate Spanish syntactic rules, and unassimilated English words may be freely inserted whenever the Spanish word is unknown. Seldom does a single type of language shifting span all three groups of nominally bilingual speakers. The reasons for these qualitative differences constitute a major research question, as does the related issue of what the bilingual grammars of all three groups of speakers have in common.