Firstly, I regret to inform you, due to a bug, all translation which have been made on the development version between the 16 October and today were lost.
We have probably lost some translators name/nickname for people who made translation, even from the beginning of the project.
I'm really sorry about that and I hope this will not happen again.
You can see this bug report for more details: http://www.playonlinux.com/en/issue-3245.html
Secondly, PlayOnLinux isn't translated in all languages, and for some languages translation aren't complete.
So if you are interested in translating PlayOnLinux in your own language you can be involved.
This is really easy, you just need to create/connect to the launchpad and make translation from that website, here: https://translations.launchpad.net/playonlinux/
Every week, translation are exported from launchpad and will be used for the next PlayOnLinux release.
If you have any questions, fell free to ask them on comment. If you find some sentence which aren't correct in English, please report them (don't forget to include location).