Exploited: The big bad Tim knows that Gregor doesn't talk much. He incorporates this into part of his Hannibal Lecture to Gregor, claiming that Gregor doesn't talk much because he feels his opinions don't matter to his True Companions. This provokes Gregor into being both noisy and evil.
Defied: Gregor realises he is quiet and decides to start talking more, to see if he likes it.
Alice: Bob, how can we get Gregor to open up more? Bob: That's a hard thing to do, Alice.
Conversed: "It's always these guys in the show to always have less lines than the others."
Gregor does have many important things to say, but is never given the opportunity to say them. This creates frustration in Gregor, and Poor Communication Kills in everyone else.
Others start to view Gregor as rude, arrogant, and apathetic because of his quietness.
Gregor learns how to keep his sentences short and sweet, while at the same time delivering them with maximum impact. So now when he tries to tell the others something, everybody listens.
But then they learn that just because Gregor's quiet doesn't mean he doesn't have anything nice to say, so they agree not to misjudge him.
Gregor agrees to only talk whenever he feels like it.
Played For Laughs: Gregor's inner thoughts are very intricate, poetic, and philosophical, but when he actually speaks, it's about something ridiculously mundane.