Hey, why should I study a foreign language when I can barely speak English?

Professors like it when students ask questions. You frequently hear professors say, "Don't hesitate to ask me a question--there are no stupid questions in this class!"
I'm not so sure.
I've heard some doozies in my day--like the student who asked me how you say "taco" in Spanish.
OK, does this one "... barely speak English?" qualify as a stupid question?
From my point of view, it's pushing the envelope.
First of all, it's patently false for this questioner to assert that s/he barely speaks English. What I think is going on in this question are two suppositions:

1. Speaking colloquial English doesn't qualify as speaking English well.
2. There's a desire to be seen as genuine, unsophisticated, authentic and down to earth.

Secondly, I sometimes wonder if the person asking me this question just secretly wants to put me in my place--in his perspective, someone who speaks more than one language must be a pointy-headed intellectual with too much time on her hands and not enough learning in the School of Hard Knocks.
Alrighty then... my answer will be brief.
If someone plays one sport well, we think, "cool!" What if they played two sports well? What if they played... three!! What would our attitude about that person be? We'd be awed.
Languages are skills that we develop, sometimes in tandem with a natural talent, just like sports or music. But anyone can learn a second language. Maybe they'll never be "fluent" (see previous post), but even Down Syndrome children can learn more than one language.
Which makes me want to ask the interrogator, are you saying you're mentally challenged?
So anyone who speaks one language can learn another. And having done so, that person will almost always report that his way of thinking about his own language and culture have been enriched.