Justin, I thought you already had a French coach - and one that, with all due respects to the designers at Nintendo, is far more shapely than a DS.
BTW, if you want French coaching deux point zero, or indeed web-based language learning more generally, you might try Livemocha.com

The way Stephanie explains it is that she knows me in English, thus addressing me in French would be like treating me like a stranger, which she finds odd. I’d add: a stranger with a two-year old’s comprehension of French, if even that.

I’m not sure what my undergraduate linguistics training would say to that, except that it’s probably highly dependent on the people involved. I’m also guessing that Stephanie isn’t interested in playing the role of my teacher, possibly because of the uneven power dynamics involved. As much as possible we try to regard each other as independent and equal.

All that said, we do talk about language a lot, and I regularly ask her what words are in French (mostly out of curiosity). She does something close to the opposite—asking whether a given anglicized French word is a valid English word (e.g. monticule came up recently). But we don’t attempt to converse with each other in French. Who knows, maybe that time will come.