Disclaimer: The Doctor doesn't belong to me, much as I wish he did.
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He just had so much in his head.
All those experiences, all those years, all those lives with their different faces and quirks.
Sometimes, words just escaped him. Or momentarily eluded him. He usually remembered what he wanted to say, or what he was going to do just then.
Eventually.
He'd discovered that hand gestures helped. To most people, it often just seemed pointless: his hands flapping about, sometimes without an apparent rhyme or reason. But to him, they were intentional, if a bit of a subconscious thing. Moving his hands helped him keep on track.
Most of the time.
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