Continuity mistake: When Elizabeth meets Lionel for the first time, her face netting disappears and reappears between shots.
Continuity mistake: Near the beginning of the film, we see the Duke of York ascending a staircase inside Wembley Stadium prior to doing a speech. Visible out of a window in the stairwell is what appears to be Kingsway (later renamed Olympic Way, commonly referred to as Wembley Way), the road that leads up to Wembley stadium and the Twin towers that were attatched to the building. However, upon entering the stadium, we see the Twin towers over on the opposite side of the stadium and therefore they are on the opposite side of the stadium to Kingsway.
Continuity mistake: When King George finishes his "In this grave hour" speech, he puts on his coat and the coat collar is flat. When they cut back to him, his coat collar is up.
Continuity mistake: When the Duke of York is telling his daughters the penguin story, the girls are shown from behind with each having an arm around one of their dogs, but immediately in the next scene, with the girls shown from the front, their arms are down by their sides.
Continuity mistake: The balls on top of the red chair change directions throughout the coronation rehearsal scene.
Continuity mistake: In the scene when Bertie is meeting Baldwin to discuss David's abdication, Bertie is shown in close-up with a speck of cigarette ash on his lapel. After a cut-away the speck has gone.
Continuity mistake: In the scene at Westminster Abbey, when King George VI enters his hands are folded in front of him, but when the shot changes, his hands are at his sides.
Answer: The technique is called "masking" and all though it can sometimes help those who stutter it is not 100% reliable. It will make some stutter less, others will not notice any difference. It would probably be very inconvenient to Bertie not to hear himself at all during an important speech, not to mention that those around him might find the whole thing strange. You can read more about research on this technique and other similar ones here: http://ajslp.asha.org/cgi/content/abstract/16/1/77.
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