I want to know how they read in their head.

A long time ago someone asked me "if you put a human brain in a pig and raised it from birth as a pig, would it be capable of human levels of conciousness and reasoning? Or would the mind mould to fit its environment (I.e. human potential is lost and it will remain a pig forever)?

I think people without monologues care raised without learning how to reason so there's no need to develooe a monologue.