Hug or handshake? The kiss? The double kiss? The triple kiss?
Saying "hello" is more complicated than just knowing the language. So much of communication is non-verbal, greetings across cultures requires you to learn to speak another language with your actions. Greetings are determined by social etiquette, relationship of the people, and geographic location.
Tips on Being Polite
If you approach situations in a positive spirit and are flexible, rarely will you go wrong in a greeting. (More)