With this reflection paper, the authors discuss the use and impact of LLMs in multi- and interlingual communication and mediation. Their main goal is to raise awareness with users, both laypersons and professionals, as well as policymakers, concerning: how LLMs ‘communicate’, how this differs from human communication and what these differences imply when GenAI is used for T&I purposes (Section 1); what impact AI is having and is likely to have in the future, in T&I professions, in terms of communication quality, workflows, job content and job contentment (Section 2.); what uninvited side-effects should be considered and duly weighed against the possibilities offered by AI (Section 3.); and whether and how AI should be included in T&I education and training, i.e. the formal education of future T&I professionals, as well as in-service training for current T&I pro­fessio­nals (Section 4.).