I thought it was a WONDERFUL movie!
BTW @Sickboy416 I'm a linguist, may I ask if you speak a second language like French or Spanish and if so, do you also stutter in that language as well?
Stuttering is really misunderstood as a lack of ability somewhere along the line, but in fact the problem that people who stutter have is that they are so sharp that they think faster than their speech organs can get the words out. So it's not that there's a hold up or break in getting the word you're trying to say out, but that by the time your mouth and such is attempting to say word x, you're brain is already planned out and sent orders for words y and z.
The movie was actually quite cool from a linguistic standpoint because the things he had the King do were right in line with the research that was later done to understand how this all worked. Like when he had him do the speech with the headphones on and sounded normal.
What's going on there is that we have basically a feedback loop in our brains for communication. For speaking, we think of a concept, assign that concept a word, then the brain tells the body to make the sound associated with that word, your mouth, vocal chords etc move, and your ears then simultaneously listen to what your body's doing to make sure it's correct or to change anything as needed.
Stuttering is actually one or more components of this system overcoming the others in speed. Usually it's your feedback loop checking for correctness based on an upcoming sound before the current one's actually made it out. This is the same thing that happens when many people try to speak a second language. They over-error check themselves.
When teaching a language, especially with adults who know the grammar and vocabulary but are just having a hard time using their language skills, we simply take them out and get them drunk. The first part of the speech system that gets numb from alcohol is the feedback loop, so people then speak without checking every sound for correctness.
Thus, they allow themselves to freely speak whatever language it is. Usually once you can prove to someone that in fact they can and for the past few hours have been sitting at the pub speaking that language, they can get themselves over the mental barrier they've created. By blocking out the King's ability to actually listen to his own speech while speaking, his therapist was doing the same thing.
The reason I ask if you stutter when speaking a different language is because when you have learned a second language later in life, there is generally a pause in the process where your mind has to think of a concept, the choose the word for that concept from a second language inventory that is basically in line with the native language but not quite as readily accessible. Then it says ok make this sound. Everything like the feedback loop works the same way, but there is usually just the slightest microsecond pause in processing that is enough to prevent the system from overrunning itself and thus causing stuttering.