Quote 25
How can there be two Pauls? "You'd call him Uncle Paul." That's too many names, my head's full. My tummy's still empty like the apple isn't there. "What's for lunch?" (2.495-2.497)
With every new concept comes new vocabulary. It's a lot for Jack's little brain to process, this whole the-brother-of-my-mother-is-my-uncle thing, so his brain pretty much shuts off and thinks of something much simpler, like lunch.
Quote 26
Near the start [of the note], there's two words I never saw before, Ma says they're her names like TV persons have, what everybody in Outside used to call her, it's only me who says Ma. (3.329)
This is the first time Jack learns that Ma has a name other than Ma (though we never get to know it). Maybe we never get to know it because Karen Jones, or whatever her name is, is never who she'll be to Jack. To Jack, the only word to describe her is, and always will be, Ma.
Quote 27
I don't see any vultures, I only see person faces with machines flashing and black fat sticks. (4.6)
Now that Jack is in the Outside, he's going to experience lots of euphemisms and idioms that seem strange to him. He doesn't understand that "vulture" is another term for "paparazzi," though it'll make a lot of sense to him once he does get it… he'll understand that the photographers are scavengers.