Me: You think so?
Student: Yes, I think my English is very poor.
Me: Why is that?
Student: Sorry?
Me: Why do you think your English is very poor?
Student: Well... I make many mistakes. Like, erm, grammar and vocabulary.
Me: Right, I see. Is that it? Is that what makes your English very poor - the mistakes?
Student: Yes. Well, no. My pronunciation is also very bad.
Me: What do you mean by "bad"?
Student: I mean, well - I have a poor accent when I speak English.
Me: You think your accent is bad?
Student: Yes, of course. You can hear it, right?
Me: I can hear you, yes. I can understand you quite clearly.
Student: Really?
Me: Yes, of course. You mean you haven't noticed that I can understand you?
Student: [Baffled look]
Me: Okay then. What about me - your teacher? Do I think your English is very poor?
Student: I don't - I'm not sure. Maybe...
Me: Wrong. I don't think your English is poor at all.
Student: Teacher is very kind.
Me: No, your teacher is just honest. But do you know why I don't think your English is poor?
Student: No.
Me: Well, this whole conversation is pretty good evidence your English is not poor.
Student: Thank you!
Me: What for?
Student: [Confused] Erm, you speak very kindly.
Me: [Sigh + lop-sided smile]
Student: What?
Me: Nothing. Let's chat again next class. Have a great weekend!
Student: You too! [Exits classroom with an expression that is both exultant and slightly confused]
:-)