Is there a text to speech program that will say each letter as it is typed in real time?
The Advanced Text To Speech features a Key to Speech mode that can be used for this purpose. I have installed it and the option can be activated after the software was installed.
As you can see in the image below, you have to check an option to be able to get the feature you want.
Download the application: http://advanced-text-to-speech.software.informer.com/download/