These are two great articles by James Hague on text processing vs visual programming.
The Unix Philosophy and a Fear of Pixels
Living inside your own Black Box
His main point is visual programming is often dismissed because it is way more difficult than text processing. It is a little bit like a lot of “stupid” things in the world such as Windows programming. They are actually quite tough to do well.
On speech processing, I guess it is appropriate to think sound programming is tougher than text processing as well. You may even think in speech processing, no one come up with a generic “Sound User Interface” IDE yet.
Arthur