I'm talking more about "thinking before you speak." As in, it seems to me that without some form of inner speech, it would be impossible to plan anything before vocalizing it, as you'd need to start talking/writing in order to actually think.
And anyway, why would that make any more sense? How would you plan the internal voice in order to produce it? An inner-inner-voice? That would need an inner-inner-inner voice?
It sounds like you have the homunculus idea of how human brain works. But this idea is nonsensical...
Can you elaborate why you think it doesn't, instead of writing single sentence replies?