Oh dear, your story sounds similar to mine: the years of "irritation", pain, then a diagnosis and small surgery followed by the need for reconstruction. (I didn't have radiation the first time round, however.) I was still teaching when I had my first surgery, went back full-time then did some part time teaching after the hemiglossectomy. I could speak clearly, still can, but it took a while for my tongue to warm up in the morning and it was harder to conduct the normal processes of teaching like reading aloud. I read the entire "Of Mice and Men" to one class though:) By that time I was in my 60s and near retirement.

In the week after surgery you will probably have a tracheotomy which means no talking for about a week. After that you can practise the tricky consonants with the speech therapist. From my experience that fine tunes the speech. The basic speech function is back as soon as the trach is out.

I haven't had nerve involvement but other people here will respond to that. It sounds as if your doctor is really onto it and has caught it as soon as possible. I wish you well. This is a shock to the system and I hope you get lots of useful info here.