Hungarian healthcare providers – as most of their colleagues around the world – engage in interaction with foreign patients, whom they do not share a mother tongue with, in English as a lingua franca (ELF) most of the time. These communicative situations pose great challenges to healthcare providers, as they have to be capable of adjusting their language use to their patients’ cognitive, linguistic and communicative-pragmatic schemata which often differ from their own. In order to develop such a capacity, ESP classes must focus on improving health science students’ awareness in exploring various ELF contexts which form ground for making informed decisions on the use of terminology. The present research aims at showing the complex dynamic nature of these ELF contexts based on empirical data collected via interviews with Hungarian healthcare providers who have extended experience in working with patients in international environments. The results can inform the everyday practice of ESP teachers in the field of the health sciences.