I didn't learn this the first time, and I doubt most other people do either. And it's a tough problem to call, because if you overdo the negative reinforcement, then you never try to do anything difficult ever again.

I think the solution to this is already described by you in the Wanting vs. Liking post -

Reinforcement learning doesn't just connect single stimuli to responses. It connects stimuli in a context to responses.

So if I do not want to overgeneralize the negative reinforcement, it seems worthwhile to pay attention to legitimate excuses - "Swahili is cool, but really hard to learn due to dearth of subtitled Swahili movies".