Fair Trial in a Machine-Translated World: AI Interpreting and the Right to Adequate Language Assistance

As artificial intelligence develops rapidly, people increasingly turn to it for interpreting and translation, driven by interpreter shortages, rising caseloads, and cost. This article asks whether AI-mediated interpreting and machine translation can satisfy the right to a fair trial of persons who do not understand the language of the proceedings, and for whom the technology fails most severely. Using a doctrinal and normative method, it reconstructs the right to language assistance under Article 6 of the European Convention on Human Rights, Directive 2010/64/EU, and the Convention on the Rights of the Child as a right to adequate language assistance, calibrated to the actual communicative capacity of the person. It argues that generic systems trained on adult speech and high-resource standard languages cannot guarantee adequacy and fail most visibly for vulnerable and intergenerational court users, with children as the clearest case, in criminal proceedings and in the cross-border hearing of the child. Situating the question within the EU Artificial Intelligence Act, Council of Europe instruments, and the 2026 Joint Statement on Artificial Intelligence and the Rights of the Child, the article proposes an adequacy standard, mandatory human oversight, and restrictions on unedited machine output in proceedings affecting vulnerable parties.