Little is known about how language-discordant mobile medical professionals (MMPs), defined as doctors who work in foreign countries, cultures, and languages, interact with their colleagues. The number of MMPs around the world is growing, and their interactions with colleagues have direct consequences for both patients' health and their own professional success. We examine the communication of MMPs in five Western European countries from the perspective of MMPs themselves (n=134) and that of their (native) colleagues (n=54). Participants agreed that MMPs could use additional training related to everyday medical language, fluency, idioms, pronunciation, humor, and local dialects. Beyond this, however, assessments diverged: MMPs generally felt confident in their communication skills (and thought others saw them as competent), but their colleagues reported a number of concerns including difficulty with small talk, nonverbal communication, and observance of (related) local cultural norms. We propose that communication training programs targeting MMPs should specifically address communication with colleagues, and should include instruction about language-related issues, and explicit discussion of local cultural norms and expectations.