This is my first post so, Hello everyone.
Ryan, I want to congratulate a great CMS.
I attach my translation for the Polish language.
The translation is fairly complete, but it requires some adjustments.
Hidden deeper setting are not yet translated.
And also the Polish translation for TinyMCE.
TinyMCE will not work without it.
https://github.com/PawelGIX/ProcessWire-Language-Pack-Polish--pl-PL-
EDIT:
I added a link to github.
ProcessWire-Language-Polish.zip
tinymce_language_Polish.zip