Today I came across an edit in the OSM wiki about the map-creating framework uMap with the good news that this webservice can be translated now by the online translation tool Transifex.
I will try to contribute whithin my knowlegde about words, vocabulary and grammar :-)
So I also added uMap to the list of OSM related websites, software or apps that can be translated in multiple languages via certain crowd-based online tools , see Translation in the OSM wiki.
Depending on certain languages, there can be done plenty of words or phrases in your "mother tounge".
Don't hesitate to contact the author of each project there if "your" language is missing in any project you want to contribute to!