I don’t have a sense of a persistent inner voice either, but I can verbalise my thoughts just fine. It feels to me like the part of my brain that turns thoughts into English sentences automatically goes to sleep when it’s not being used. And that brain power can be used for something else.
When I’m doing particularly hard programming work, I can’t have words said near me. Even music with lyrics messes me up. I think because it wakes up my “thoughts to English” pathway and that gets in the way of my “thoughts to code” pathway.
Anyway, I don’t want to be cured. There’s nothing wrong with my mind. If anything I feel sorry for people who can’t turn off their inner dialogue, because it means they can never use those neurons for other tasks - like maths or programming.
Personally I can talk while programming if an interviewer wants that, but I’ll be a bit dumber at the keyboard than if I sat in silence.