I can't understand all of the Thai but this guy really seems to hit the nail on the head in terms of how Thais mispronounce English and why. If you're Thai and you haven't spent a lot of time living in an English speaking country it's worth checking out. Just those small changes he suggests make a big difference.

English is difficult but not too difficult :'(

Because you're smart!. :-)

come on, Bill

you know that how I am stupid...

this teacher is so handsome :-)