I was hoping that someone who had theirs on the base of tongue would answer as their experiences are probably more similar to your husband's situation.

I had a partial glossectomy, but my tumour was on the side of my tongue & off of the floor of the mouth. They performed the radial forearm free flap surgery on me (along with a neck dissection). Then about 5 or 6 weeks after surgery I had 5 weeks of radiation. No chemo in my case.

My speech is somewhat affected. Most people can understand most of what I say, but some words give me problems. Particularly those with the same letter back to back. Occasionally I will try to say a particular word & be unable to pronounce it adequately, so have to pause and come up with a different word with a similar meaning.