I know how to say good bye in three different languages. And they are Russian, German, and Spanish. Their pronounciation is pretty different but they have one thing in common, they are short. These are used to say good bye to your relatives and a different version to your boyfriend/girlfriend. Here are they are:

I know you all know this one, but I just want to do it in English first:

English- Good bye: relatives/family; see ya: boyfriend/girlfriend

German- (Only know one version of this one)-Guten Abend: Everybody. (It can be used a good bye and goodnight)

Russian- Poka: Girlfriend/boyfriend; Dosvidaniya: family/relatives

Spanish- Adiós: Everybody: family/friends/boyfriend or girlfriend.

I do not speak all of these languages but I do speak English and Russian fluently. Some of the people I know taught me this and I hope that this helps you talking to someone in a language you do not know very well.