Check out the translation industry. It's a fairly niche market, with its own quirks. There is a good book that gives an overview of how the industry works, but I can't remember the title atm. It has a yellow cover and some cartoon drawings inside... :) If you're interested I can dig a bit more and find it.

There is software for translation management, which is essentially project management, but because of the intricacies of the business there is specialized software for it. There are maybe 2 or 3 main competitors, all of which do the job but are fairly awful to use. Then there are a handful of products which come from computer-assisted translation (CAT, which is different from machine translation), and try to capture the project management part as well. Because their focus is on CAT, they're also not excellent in the management aspect.

If you want to capture the whole spectrum with all the edge cases, it's going to be a very complex product which will require a lot of user research and take a fairly long time to build. But there might be an opportunity to go to market earlier, with a subset of the functionality, and build from there.