Jake "talks" like this all day long - not just when he's reading books! We love it. I can't believe when my parents tell me how quiet I was as a child - I'm not quiet now, and neither is Chris or Jake :-)
Jake has many nicknames: Jakeman, Jakey, monkey man, Jakers, Jacob (his real name which my dad is the only one that calls him that). I always call Jake "Jakey" and if you listen closely it sounds like he says Jakey a couple times in the middle of this clip.
And yes, if you were wondering - it is the middle of summer and Jake is wearing a long sleeve shirt - you would think it was fall already with our cool Calgary weather!