If you're struggling to figure out how to use this function in a project that only supports certain languages, move along.
Unfortunately, this function doesn't let you specify languages supported by your project - and since the internal header parsing and negotiation logic isn't exposed in any other way, you'll most likely want to ditch this function and go for a custom implementation of the same thing:
https://github.com/willdurand/Negotiation