Alpaca
Your questions are not naive at all. As noted above, it's impossible to get straight answers on these important questions from the doctors. For what it's worth, after my tongue & jaw surgery plus flap, my speech is intelligible, although much slower than before. As your tongue recovers mobility, your speech will improve. I also had a palate prothesis made since I could not get my tongue all the way up to the back of the palate. I also strongly echo the importance of getting speech therapy as others have posted.
I took an early retirement to focus 100% on recovery.
Take a look at the main OCF page on treatment and surgery.
charm
There will be what we call a "new normal" after the surgery