Interesting to note regarding very early [original?] Chinese immigrants of locales such as Sukhothai, Chiang Mai, Ayutthaya, etc were not Mandarin or Cantonese speakers - but local languages/dialects from the southern provinces. Long before the "newish" wave of predominately Mandarin speaking Chinese of late 19th century BKK.
The early upcountry Chinese folk were the movers and shakers of commerce and trade.