Here's my theory on those internalized voices - it's true for me, anyway:
Those statements - the putdowns, punishments, dismissals - are actually my pain trying to tell me "what hurts"... and why. The repetition of those unkind, thoughtless - and even malevolent - internalized statements, are my pain trying to get my own attention and DO SOMETHING about it. The most common thing I would do is protest... and of course, the punishments & judgements escalated as needed to quell the protests. Voila - voicelessness.
And what I've realized recently, is that all I have to do is acknowledge the hurt, the boundary violation, or what I've realized on my recent road trip - is FEAR... listen to it, understand it, agree with the fear or pain and deal compassionately with myself... for me to stop being in the emotion long enough for me to ask: is there any evidence that there is any truth to this particular judgement, or painful statement, or fear??? And then it goes away, until the "next one" comes up.
I feared most, that my mother was dead-on accurate about me: I really was a spacey, day-dreaming, incompentent fool. That I needed all my anxious, OCD-like "routines" and processes -- or I'd STOP APPEARING NORMAL... sort of emotionally naked in public and this would abominably embarrassing. (uh... I AM normal... and I have nothing to hide emotionally... I think this is a projected fear; not a REAL fear, in other words.) This and other other fears came up as I drove 1000 miles round-trip over the last 4 days. Wasn't really "thinking" - just driving, paying attention to driving - and over & over these fears came up, I did what I just described, and it went away again... gradually becoming less & less. It was just what I did... and it seemed to work.
I began to FEEL that those old fears were nothing more than how I protected myself from real statements that hurt, were unfair, unjust....
... and that I have learned many other ways to protect myself... though I need to less than I did long ago, because OTHER PEOPLE don't treat me like that (and for the few that do, I have new methods of defending myself). It was time let the fears pass into "history"... fade away... tossed out of the car like a gum wrapper, before people cared about littering. The whole road-trip was full of things like this. I'll write more about them, later.