I can choose between two English versions of this mod. Which one is the right one or where is difference?

If there were a 'right one', there would be a 'wrong one' as well, but that one wouldn't be available as an option, obviously.
Choose whichever you wish. The original one is my creation with Aldeth the Foppish Idiot's corrections, while the other one is a revised version, by olimikrig. The latter one is closer to Baldur's Gate's style of dialogs, and there are some good improvements in the text. As far as primary content is concerned, there is no difference. (No semantic difference.)