The article is from ChinaExpert.com website, due credits to this site. Link to original article - http://www.chinaexpat.com/2011/08/10/the-teochew-chinese-not-hokkienese.html
Here are some excerpts: They’re Han, Chaozhou people, but not if you ask them. Not Zhong guo ren, but Tang ren are the Teochew. Not people of the Middle Kingdom but of the coast, they’ll tell you, and their home is the mountain on the sea. The “People of the Tang Dynasty” appellation intrigues, for it was the much later 12th century Jin invasion of Northern China that pushed today’s Hokkien and Teochew south to Fujian and Guangdong. Tellingly, the Hokkien and Teochew dialects are quite similar, not only to each other but to Korean, itself a vassal state of the Tang Empire. Even more tellingly, a Teochew will forgive you for calling him Han, but will start wetting the kitchen cleaver if you call him Hokkien.
So if you're a Teochew, a person of Teochew descent it is indeed and interesting discovery to know your roots and its various connections. Ya, even connection with Korean Hangul language!
And pretty true about some Hokkien and Teochew tension! No offence (again a Teochew trait of non-confrontational and endurance) but Hokkien is much a stiffer, rougher, louder language and seems to always lord over Teochew people (e.g. in Malaysia and Singapore). Teochew people often relent and will mingle and speak in Hokkien or Cantonese. In a starting conversation, it is often sort of "enforced" to speak other than Teochew. And the teochew just picks up the language.
But I never ever seen a Hokkien nor Cantonese being humble and want to learn or speak. Or listen! It is almost certain the protagonist will give a weird look if we do not speak their lingua franca.
Only yes alas, once when I was in Hong Kong the land of Cantonese. And I was at a department store shopping centre. There was a bunch of presumably wealthy teochew businessmen. They could be from Shantou or elsewhere or another country I don't know. But they went to this shop and started asking price and questions in teochew. The sales girl can't speak but obliging helped and listen. Never "enforcing" another language upon them.
That massive migrant Teochew population provides an air duct through which to sneak back to our theme of knowing less and less the farther you travel. For only by truly stepping into their alien identity, and paradoxically assimilating around the globe, did the Teochew transcend as a subgroup.