1. Bonjour (French)
2. Hola (Spanish)
3. Hallo (German)
4. Hallo (Norwegian)
5. Ciao (Italian)
6. γειάσου (Greek)
7. Ni hao (Chinese Mandarin) or "Nong hao" if you live in Shanghai, like me (npfan: I'm pretty sure that means "How are you?", but "Nei ho" in Hong Kong or Canton (Guangdong) Province)
8. こんにちは (Japanese)
9. Bring palm face down as in a salute down from forehead (American Sign Language)

We had this topic some time ago already...