There are several dialects of Thai although in this web site we use Central Thai, the most common form of the Thai language. The main influencing factors that determine if people speak a dialect are their family, the school they went to and their general environment and neighbourhood.
Thai people do not expect foreigners to be able to speak dialect and almost all would laugh if they heard a ฝรั่ง farang speak dialect.
Very few people know or speak so called Royal dialect. Any words you do come across are usually very grandiloquent. When we studied polite particles, it was said that male royal family members usually say ค่ะ instead of ครับ.
From the North east of Thailand, Isaan shares some similarities to the Laos languange. Isaan people have problems speaking Central Thai without an accent. When someone mixes an Isaan word into conversation, his friends might tease him that he ตกลาว dtok lao. The majority of people don't mind this joke, even in Isaan. People from Nakhon Rachasima are sometimes said to speak ภาษาโคราช pasa kohrat.
From the Northern region of Thailand, Lanna is also similar to Isaan; this dialect is known as ภาษาเหนือ pasa neua. People from Chiang Mai say that they speak ภาษาเชียงใหม่ pasa chiang mai and that they speak slowly with long sounds; other people who speak Lanna speak faster with different pronunciation.
Southern speakers also have problems speaking central Thai without an accent and are sometimes said to be ทองแดง tong dairng. Southern people say ไม่พรือ mai preu for ไม่เป็นไร
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