I'm guessing that the main reason they require you to go through their "preferred partners" is that their job is to insert annontations that the speech generato

I'm guessing that the main reason they require you to go through their "preferred partners" is that their job is to insert annontations that the speech generator needs to make it sound good. I wonder if this is because it's difficult work, or if the tools aren't user friendly enough to put in the hands of untrained users. If it's the latter I suppose that sooner or later we won't need to go through the partners.