Interesting. I've been actively suppressing verbalization whenever it comes up as far as I can remember -- it is annoying af, as annoying as those silly tunes that get stuck in your head.
Not sure if that actually affected amount of internal monologue I do have, but I definitely don't have it on all the time. Mostly when rehearsing an actual past or expected conversation.
Do you have any tricks on suppressing verbalization? I've found that it feels really wasteful when I realize that half my thoughts are just acting as a translator for the abstract side, instead of keeping it abstract until I get to something I need to verbalize.
Maybe try reading using a speed reading app. I use Comfort Reader [0]. When the words fly by really fast you have to stop sounding the words in your head or won't be able to read the full sentence. For me thinking is like writing and reading to myself so it helps.
Not sure if that actually affected amount of internal monologue I do have, but I definitely don't have it on all the time. Mostly when rehearsing an actual past or expected conversation.