There was a story in Japan press about a Chinese woman who switched her left and right fingertips (ooouch, surgicaly, in China) trying to fool the Japan Immigration.
Since the story made it into the media, they got her.
"South are more likely to be Kymer origin rather than Lao."
Is it "Kymer" or Khmer (Cambodia)? My wife can peak Khmer.
Europe, the same distance, like from Stockholm to Rome and you fly over many countries, languages (mutualy unintelligable) , legistratures and cultures.
You would know that. The name (half derogatory name for all foreigners, "farang" is a deformation of Thai pronounciation of "French". Thais never forgave the French cutting the state of Laos out of Thailand.
Indeed, Thailand is not a reper of democracy but Thai people are much richer, well off and happier than Lao people.
My daughter, a Thai national, can barely understand Thai in Wang Nam Yen (near Cambodia) or in Korat or Udon Thani.
She would say "I know what is being talked about and what is happening around me".
Isan, instead of calling us "farang" say "buksida".
Married at Sathorn City Council, Bangkok, our marriage certificate (2008) has been accepted everywhere, in Japan too. We are not after a marriage visa but we could.