Many language pairs chosen in language switching studies differ randomly on multiple linguistic levels, thus obscuring the nature of switching costs. Contact-induced languages, i.e., creoles (e.g., Spanish-based Palenquero) and mixed languages (e.g., Media Lengua), having arisen in intense language contact scenarios, relate systematically to their source languages by displaying high proportions of cognates or shared grammar. This configuration can speak to the relative contribution of lexicon and grammar to switching costs. Results from a production and comprehension task show that switching costs are systematically tied to a language pair's grammatical distance. This suggests that switching costs may result from the re-generation of the morphosyntactic frame on switch trials. Emphasizing the value of testing psycholinguistic theories outside of the usual Western populations, the current study provides insight into the degree of shared mental representations between contact-induced languages and their source languages.

This study investigates the relationship between intra-sentential codeswitching restrictions after subject pronouns, negative elements, and interrogatives and language-specific syntactic structures. Data are presented from two languages that have non-cognate lexicons but share identical phrase structure and syntactic mechanisms and exactly the same grammatical morphemes except for pronouns, negators, and interrogative words. The languages are the Quichua of Imbabura province, Ecuador and Ecuadorian Media Lengua (ML), consisting of Quichua morphosyntax with Spanish-derived lexical roots. Bilingual participants carried out un-timed acceptability judgment and language-identification tasks and concurrent memory-loaded repetition on utterances in Quichua, ML, and various mixtures of Quichua and ML. The acceptability and classification data show a main effect for category of single-word switches (significant differences for lexical vs. interrogative, negative, and for acceptability, pronoun) and repetition data show significant differences between lexical vs. interrogatives and negators. Third-person pronouns (which require an explicit antecedent) also differ significantly from lexical items. Logical-semantic factors may contribute to code-switching restrictions.