[sudo_raspberry]

I find a similar response whenI say United Statesians either. The sentence "United Statesians speak American" could trigger a few people I know.

[aasasd]

Gotta say, I can see the dissonance there: you use the specific ‘name’ for the country, but the two continents for the language.

[JadeNB]

That's a good point. Even as someone who calls my language American and refers myself a USian in conversation, I do think I'd have trouble calling the language I speak USian—but, as you point out, calling it American is painting with a very broad brush indeed. Maybe "USian English" is clearest.