The preferred audience helps you choose the preferred audience for this post. Choose the people you'd like to reach in the News Feed (this feature is available for Facebook only).
Preferred audience allows you to schedule / publish content organically by selecting the audience you want by interests, age, location and language.
Using preferred audience you can schedule content for English audience only, and then create another post for the French audience.
Here's how you can do it.
Go to the post settings, right here and select the preferred audience.
2. Then, click on it and select Audience restrictions > Languages
Then choose the language you want this post to focus on.
You can also select Preferred Audience when creating a post, right here.
Unfortunately, creating a multi language like on Facebook is not available due to Facebook API limitations.