In Thailand, the greeting word "Hello" is replaced by the word "Sawasdee" (pronounce, sa-wad-dee) with a suffix word "Krab" if you are male or "Ka" if you are female to make your speech more polite. So, it will say "Sawasdee Krab" for men or "Sawasdee Ka" for women. How people feel when you say those suffix words may be as same as when you hear the word "Sir" behind a sentence.