There are no language switching costs when codeswitching is frequent

International audience Aims and Objectives/Purpose/Research Questions: There is ongoing discussion as to the cost of language switching, with some studies indicating high cost and others showing low or no cost. The main research question in this paper is whether there are language switching costs in communities in which codeswitching is frequent. Design/Methodology/Approach: We conducted two on-line experiments, i.e. a picture choice with sentence auditory stimuli and a word recognition task in sentence context. We constructed 16 sentences with differing degrees of ecological validity (16 sentences x 4 versions = 64). The sentences included verbs with different language preferences in natural conversations (L1, L2, or both). Data and Analysis: Thirty-seven simultaneous L1-Romani L2-Turkish bilinguals participated in Experiment 1 and 49 in Experiment 2. To analyze the results, linear mixed models (lmer) were constructed using the ‘lme4’ package in R.Findings/Conclusions: In Experiment 1, participants responded significantly faster for the all-Turkish sentences, followed by the mixed Romani-Turkish sentences, and the two types of ecologically non-valid sentences. However, there were no processing costs for the mixed sentences when they contained Turkish verbs that are more frequently used in Turkish in the spontaneous conversations. In Experiment 2, reaction times were similar for Turkish verbs (with Turkish verb morphology) in a mixed Romani-Turkish or a unilingual Turkish sentence.Originality: Taken together these findings indicate that language switching costs in comprehension depend on the frequency of codeswitching in the bilingual community, as well as on exposure to specific lexical items.Significance/Implications: The Romani-Turkish data support a usage-based approach to bilingual processing and confirm the need to conduct experimental research that takes into account the communicational habits of the participants.