It seems, however, that Colin Firth is having trouble shaking the "learned" impediment. As you can read at this link, since wrapping the film and carrying on with other projects, he has found that at times, he finds himself lapsing back into the stammer that he learned for the role. He also indicates that when be thinks about the stammer, the worse he finds that it gets. Quoting from the article, "I guess old habits die hard." You can read the story at this link, which is a different publication.
When I think about it, I can honestly understand how something like that can happen. From what I have read, much of my stutter (I can speak only for myself) is learned behavior...a habitual form of approaching speech. While I maintain that it is an impediment, probably partly genetic and neurological, I believe that I have taught myself bad habits over the years that contribute something to my own condition. For example, when I hear a ringing telephone that I must answer, my stomach muscles immediately contract and seize up in anticipation of having to get out that first word, especially if it a string of words I must emit, such as one must do when working for some company. "Hello, this is Southwest General Hospital, how may I direct your call?" I made that up, by the way.
Perhaps if I were to go through some kind of behavior modification therapy, some of those habits could be unlearned, helping me to be, at least, more fluent in some circumstances. I can't say for sure, I only speak what seems logical to me. Of course, there are many other times when my speech is dysfluent for no apparent reason at all. For example, when I am at home with a family member or loved one and I am completely at ease, there seems to be no habitual behavior associated with my stammer. This indicates, again, at least to me, that much of my impediment is uncontrollable.
I find it beneficial that Colin Firth is such a notable celebrity because that will allow his predicament to be somewhat played out in the public eye where we can all see where it eventually leads. Will he drop the habit on his own, or will be require some kind of speech therapy to overcome it?
Can stuttering/stammering be learned...to the point that one know longer has control over it and requires professional intervention to remedy it? That would be an interesting case for the medical books. What do you think?