don't ever answer something that u (you) don't understand, then :D
it's terribly stupid to do that (such answer can be very stupid), so people may think you're retarded with total lack of knowlege responder to their questions..
english is the the most important international language in the word these days, so learn it well enough first before you decide to converse with (talk to) others (foreigners) ;)
i speak 4 languages fluently and i can understand more or less 10 other languages, so no excuse that you can't learn just that one in addition to your native one :)
i don't have time to teach you this language..
bad communication makes bad relationship..
i don't need to be frustrated with someones undeveloped english skills that much as yours because you were lazy to learn it..
everyone can learn that language even in 5 - 10 years if this is so difficult for them..
others can learn it just in months to communicate better than you're doing it here..
it should be a shame to the thai people that they're just too lazy to learn it while there're lots of free english lessons (free material including free audio files) on the internet these days ;)