I already know how to speak. My brain just happens to get these roadblocks which make it difficult for me to speak fluently. The doctor proved his point by speaking into a toy microphone. His speech became instantly fluent, and he was able to talk as fast as humanly possible without a single stutter. Changing the pitch of a person's voice via the hearing aid also seems to create the same fluency effect.
Prototypes are under way, but more funding is needed.
Equally promising is the discovery that visual stimulus has a resetting effect similar to the secondary audio delay. If a stutterer talks while simply watching someone mouthing words, they are also empowered to speak fluently without encountering stuttering events. Kalinowski demonstrated this phenomenon by reciting the Pledge of Allegiance twice - once unaided, then again while watching a graduate student mouth unrelated words. The first performance was characterized by several stuttering episodes. But during the second recitation, the visual cue restored Kalinowski's speech to perfect fluency.