Copilot doesn't translate in French when I speak French to it, it only understands English

First, check whether Copilot is mishearing your French or hearing it correctly but replying in English.

If you’re using the keyboard’s microphone to dictate, set the dictation language to French. On iPhone, add French under Settings > General > Keyboard > Keyboards, then switch to that keyboard before dictating. On Windows, select a French input language before using Win+H.

If you’re using Copilot’s own voice mode, those keyboard settings don’t control it. Start a new conversation and type: “Réponds uniquement en français,” then try voice again. Check the transcript, if available, to see whether your French was recognised correctly.

If typed French works but Copilot’s voice mode fails on both devices, report it through Copilot’s feedback option with a short example and the incorrect transcript. That helps distinguish a speech-recognition issue from a translation or response-language problem.