There hasn't been a really high profile stammer in the UK since King George VI died in 1952. Colin Firth does an incredibly realistic job of conveying how it is to be stuck in a block with no control over your speech, part of the audience staring at you and part staring at the ground. No film has ever done that before. But we need to remember that the action takes place about 75 years ago, so it is history. From what we know it's a fairly realistic re-enactment of what was going on at that time.