Enlightenment from the shower: My lack of confidence in my French is due to the way I speak English. Ideas in English never occur to me in simple language; they come to me fully formed with idioms and metaphors and circumlocuction and ironic understatement. Because I learned French as an academic subject with one-to-one equivalent vocabulary, my French isn't nearly as rich.

When I'm writing, I have time to think and reduce my English ideas to something simpler that I can render in French, but when I'm speaking I don't have time to do this. The result is a total lack of confidence in my French because I can't instantly render the unnecessarily complex English thoughts that pop into my head.