Communication and learning are intimately interconnected; choosing to communicate or not is one of the most important decisions a language learner makes (Gregersen & MacIntyre, 2014). A learner’s willingness to communicate (WTC) is defined as the probability she/he will choose to initiate communication given opportunity (MacIntyre et al., 1998). In multilingual contexts, WTC will involve situated assessments of the ‘usability’ of different languages made by learners/speakers. In contexts of adult second language education, such as Sweden, a contact language (usually English) and the target language (Swedish) both provide viable communication options. This presentation reports on a mixed-methods, individual-level, time-serial study (n=6) examining the WTC of adult migrants learning Swedish for whom English was a contact language. The research examines WTC in two languages during a period when learner/speaker functional skills in Swedish first develop. Results of change point analyses reveal patterns of co-evolutionary development. They show how WTC is characterised by patterns of stability and ‘change points’ when shifts into new communicative orientations occur. Findings are discussed in the context of (i) the conceptualization of WTC in relation to the multilingual and dynamic turns in SLA (Ortega, 2014; Ortega & Han, 2017), and (ii) educational practice in contexts of multilingualism.