Transcripts are always helpful, yes, specially for Callum's mumblings.

I always feel like he has a 'normal' guy dialogue running in his head, but it only comes out when he 'forgets' about the cameras.
Spot-on observation! Some interviewers are better than others to let him express what he really has in mind, and then, he's still twitchy but definitely more at ease.

Paul Gross is really a funny guy. And I bet that Callum was really happy to have him around in some interviews.