A new, foreign language
First of all, we can and we do not want to create an online language course at this point. There are competent providers and it takes time to learn a new language. We would rather say something for general understanding. For basic clarification: The Thai language (Paasáa Tai) is the national language. It is a tonal language, where the words can have different meanings due to different emphasis on the syllables. But that's worse than it sounds, basic concepts are easy and quick to learn.
Besides Thai, English is the common language. However, that does not mean that everyone is fluent in the English language, on the contrary, many Thai can speak the English language in fragments, some not at all, and others in turn speak English very well.
"Blessing in disguise". Speaking and understanding Thai is one thing, reading or even writing a completely different one. While you can still try other languages on the basis of the familiar spelling way to speak or even understand, the use in the Thai language is not helpful. For the tourist Thai language is in many areas not really bad, there are signs often Thai next to a familiar spelling in English labguage we foreigners can read and understand.
Last but not least, to make it even more exciting, there is a distinction in addressing certain words, whether one speaks as a man or as a woman as someone. The simple greeting "Good Day" with Sawadee follows in polite form a Sawadee Kha (if a woman speaks it) and Sawadee Krap (if it man uses it). The same applies to the word "thank you", khop khun kha or khop khun krap. Kha and Krap are the courtesies and stand at the end of a question, a request or a statement.