There are 3 ways to say "Thank you" in Thai.

منذ عامين

There are 3 ways to say "Thank you" in Thai.

khɔ̀ɔp khun , khɔ̀ɔp cay, and khɔ̀ɔp  phrá khun

I am sure that you may hear " khɔ̀ɔp khun " when you travel to Thailand.
What is the difference between these?

Let's talk about It.
Someone helps you to do something. We always say khɔ̀ɔp khun and khɔ̀ɔp cay.

khɔ̀ɔp khun is a general speech for everyone. 
We can say "khɔ̀ɔp khun" to people who are both older and younger than us.

khɔ̀ɔp cay is good for people who are younger than us.

khɔ̀ɔp  phrá khun : we always say this to people who are older than us, and we respect them very much.

Note: Thai people really respect older people. This is the Thai culture.

Thank you   ==    khɔ̀ɔp khun                   ขอบคุณ
                                  khɔ̀ɔp cay                       ขอบใจ
                                   khɔ̀ɔp  phrá khun        ขอบพระคุณ