It would be possible, though, to write a stand-alone program running under Emacs as a process. In Emacs you could support selection and correction of text by speaking phrases. If they aren't there, look for the alternates. Of course with a system like this, you also need some other program that enables you to control the rest of your machine. There seems to be a facility to allow different programs to cooperate in their use of the microphone, however, so I don't think this would be a fundamental problem.
Software projects are notoriously difficult to estimate.
I think it would take much longer to have a high-quality system that really handled all the things that any dictation system should have, and I'd probably be adding new features forever. In comparison to its very small volume, it is quite interesting. The best thing about it is that when you post a question you get an answer from IBM right away. Not that much seems to be going on, though. If people outside IBM are developing applications using IBM's kits, they aren't discussing it much on the list.