Our University is working with another University in South America on a single development project. While some of their professors have a good grasp on English, most of them speak only Spanish.

We've developed a fairly large design document and we're currently working on technical documentation parallel to development. My question is what's the most efficient way of managing these documents? Ideally I would like to create a Word document that includes both an English and Spanish translation in the same document (to keep both documents in sync rather than trying to manage two documents).

Is this possible? Are there any tools available to help multiple developers of different languages work on the same project?