if your traveling in Thailand...they perfectly understand Thank you. Don't make a fool of yourself by saying kop khun krap and pronounce it wrong like 95% of foreigners or when you starting giving the wai to everyone but not doing it properly...when your travelling (that is the word he used) stick to the basics.
not true..i have traveled to over 50 countries and i don't speak 50 languages. If you plan on making Thailand your home...well then that is a different story and yes it's good to know some of the language.
you're right Maxim, i had my discussion with them over the phone ( Covid period) so it was a slow period and they guided me to their appt schedule online and of course at that time it was very easy and fast.