You are right about the fair skin Chinese Issan people. All the while I thought all Issan people are dark skin. Until one day, I went to Udon Thani and stayed one night there (actually I was on my way to Nong Khai). Boy, I was real surprised to see quite a few Chinese looking Thais and a number of Goldsmiths shops there own by them!!
I can't really tell whether a dark person is from Issan, Klang or Tai. But of course when they speak their local dialects, I can tell. Somehow, those Klang people outside Bkk also speaks a little different from the Bkk Thai.
Where is klang? Does it refer to the north? I thought they were called ngai?
When i was a child i visited the death bridge the japs forced the allied prisioners to build in thailand. It's the inspiration for the movie the bridge over river kwai. I asked my frens about this bridge and they were clueless.
I should have figured the r and l pronunciation thing at that time. 
Got this kind meh, they tell me this is THAILAND. 
