Questions about TranslateWiki and IMSLP
Fragment of a discussion from Extension talk:Translate
Q1: No. The extension provides the same functionality as in translatewiki.net, but without the community and infrastructure that translatewiki.net has. Translatewiki.net accepts only software projects, which adhere to the requirements open license and guarantee quick handling of i18n related issues.
Q2: Existing content needs to be ported manually. That is because Translate extension handles translatable pages in paragraph sized units and it can determine those automatically. And that is lot of work. You can always try it out with new content, and if it fits, start converting the old content gradually.
