Art Thieme does it at the very end of Craig Johnson's hilarious song To the North Woods.

I'm trying to remember if my dad ever did it. If he did I think it would be because a lot of the songs he sang were such poetry, or even were poems made into songs and so, speaking a part of them, would have been natural. We had a lot of poetry and songs in our family, so I think it must've been so at least once in awhile. I'll have to ask my siblings.