Goodbye in Lots of Languages:
Common Languages:
* English: Goodbye, farewell, see you later, later, take care
* Spanish: Adiós, hasta luego, hasta pronto, chao
* French: Au revoir, à bientôt, salut
* German: Auf Wiedersehen, tschüss, bis bald
* Italian: Arrivederci, ciao, a presto
* Portuguese: Adeus, até logo, até breve
* Russian: До свидания (Do svidaniya), пока (poka)
* Chinese (Mandarin): 再见 (Zàijiàn), 拜拜 (Bàibai)
* Japanese: さようなら (Sayōnara), またね (Mata ne)
* Korean: 안녕히 계세요 (Annyeonghi gyeseyo), 잘 가세요 (Jal gaseyo)
Less Common Languages:
* Arabic: مع السلامة (Ma'a as-salaama)
* Hindi: अलविदा (Alvida)
* Dutch: Tot ziens, doei
* Swedish: Hej då, adjö
* Polish: Do widzenia, cześć
* Greek: Αντίο (Antio)
* Turkish: Elveda, hoşça kal
* Hungarian: Viszlát, szia
* Czech: Na shledanou, ahoj
* Finnish: Hei hei, näkemiin
* Danish: Farvel, hej hej
* Norwegian: Ha det bra, hei hei
* Vietnamese: Tạm biệt (Tạm biệt), chào (Chào)
* Thai: ลาก่อน (Laa gorn)
* Hebrew: להתראות (Lehitra'ot)
Bonus:
* Pirate: Ahoy, matey!
* Yoda: "See you, I will."
* Valar Morghulis (Game of Thrones): "All men must die."
This is just a small sampling of the many languages spoken around the world. The best way to say goodbye in a particular language is to learn the appropriate phrase from a native speaker.