Giving difficult feedback across a language barrier

Feedback is usually taught with softening language — hedges, questions, indirect phrasing. Much of that does not survive translation, and some of it is heard as approval by someone working in their second or third language. What tends to work better is plain, direct sentences, one point at a time, a concrete example, and asking the person to say back what they understood. It feels blunter than the training says it should. How do you handle this on a multilingual site, and where have you seen a message land as the opposite of what was meant?