["TESOL Quarterly, EarlyView. ", "\nAbstract\nPrevious research demonstrated that communication anxiety reduces L2 learners' willingness to communicate and communication frequency, but left unexplored its impact on performance. The current mixed‐methods study investigated factors impacting L2 communication skills. Exploratory Sequential Phases involved audio‐recorded interactions between an English native speaker (NS) and 80 L1 Chinese participants who recounted interactions with NSs and nonnative speakers (NNSs). From these data, the Communication Affect Scale (CAS) was developed, with items emphasizing positive affect and experiential reflection. Analysis of 240 participants' responses extracted three factors: Affect when Communicating with NSs (CAS_NS), NNSs (CAS_NNS), and Sociability in English. In the Convergent phase, 410 participants responded to three questionnaires (CAS, Strategies, Perceived Competence [PerComp]), provided L2 use data, and interacted with the NS. SEM revealed that positive CAS_NNS, greater PerComp_Proficient, more NS interactions and L2 writing predicted higher communication scores (outcome measure). CAS_NNS drove strategy use, predicting greater PerComp_Basic&Intermediate. Qualitatively, NS interlocutors offered linguistic scaffolding (“I can learn more…”); NNSs provided emotional scaffolding (“We're in the same situation.”), but required greater speaker effort, which enhanced skills. Replacement of competent L2 user identity with L2 learner identity in the United States was frustrating (“So where am I?”), but exercising agency beyond the “comfortable” zone and developing confidence (“other Chinese…not confident…now I dare to be the minority.”) were gratifying.\n"]