Can I translate Post Affiliate Pro for Quality Unit

Yes you can and you are very welcome!

First, contact our online support to see if we need new language translations. If we do, you will be given a license with 30 day validity. In this time you have to create the translation. The translation has to be done at least to 98%. If you do not translate it in 30 days and there is no progress in your work, your license will expire and you won't be able to use it anymore. If there is any progress and you simply need more time, approach us and we will extend the license for a few more days.

If the language is complete to at least 98% and content is approved, we will give you a 40% discount on your subscription. If you provide subsequent language updates (every 2-3 months), the 40% discount will be prolonged accordingly. 

You can also participate in translations by creating an account in Crowdin and translate from there:
https://crowdin.com/project/postaffiliatepro/