How can I start a new project?

MediaWiki extensions in svn.wikimedia.org will be supported if they adhere to the coding conventions, and if there are no other hurdles (not to be expected here).

For documentation, etc, you could consider using Translate Page Translation if you are already using MediaWiki. That is something that is in my opinion best supported inside your own community.

Lists of terms, and that kind of stuff, especially of kept under version control, is something that, provided there is file format support, can be added a message groups in translatewiki.net. I would welcome that.

Please drop me an e-mail (siebrand AT translatewiki DOT net), so we can discuss details offline. See Translating:New_project for some criteria that we have for accepting new projects.