Do you know any collaborative translation tool?
I've seen the suggestions in this answer, but I'm specifically searching for a tool to translate books (so large documents made of paragraphs, mostly), with possibility for other users to check/correct/validate other users' translations, roles (admins, validators...), and if possible something that has a nice API so I can convert the result into LaTeX to publish the book.
The tool could be SaaS (preferably free) or open-source (to be hosted on LAMP or similar).
I recently know this project - Narro.
It seems an open source collaborative translation tool. It only needs a server with PHP and MySQL to deploy.
Haven't tried it out but I think it should be something that you are looking for.
Otherwise there is another website of collaborative translation: https://crowdin.net/
I'm not sure if it meets your need but I think it's worth to try.
I have been working with a really useful collaborative translation tool, http://poeditor.com/. It allows you to create as many projects as you wish and make them public for contributors to join and translate for you. Contributors can collaborate on translations with no limits and the work space is really nice and simple to use.
If you are willing to release the text under a CC like licence and if you are translating between English and Spanish, Italian, German and few other large European languages, and if you are OK with that you cannot dictate who can and who cannot edit the translation, you can try uploading it for the Immersion feature on duolingo.com language learning site.
From a cursory look I figured it is impossible to make the translation editable to everybody, you need to grant the edit right to particular Google Account holders. That is bad for me, but others can be OK with that.
These tools work with po files.
It provides automatic similarity search in already translated strings, allows some forms of communication between the translators, has support for some simple validation (warns if the translation is wildly different from the source string) and so on. For a demo, you can take a look at for example the Universal Subtles project there.