1. If your international target audience speaks different languages in more or less the same proportion. For example, you operate on the tourism industry and work with English, Chinese and German speaking audience.
On Facebook, you can streamline your process with Global Pages. You can set up localized versions of your cover and profile photos, apps, milestones, „About" information, news feed stories. An English version's cover might say „Hello" while users visiting from German-speaking regions would see a version welcoming them with Hallo. So, create a single brand identity with Global Pages.
Don't forget that you can do targeting of your updates by language!
For example, your updates in English should appear only in the news feeds of those whose language is set to English, while your Russian or German updates will appear to only those set to Russian or German accordingly.
In turn, if it's about Twitter, the best approach would be to create separate Twitter accounts in different languages.
Imagine a situation when you go to a party with some friends and a few of them, from the same country, start speaking in their native language that you don't understand? This is how your Twitter followers feel when they notice you're sending out different messages in different languages.