who's the guy at the end of ummagumma reading poetry in a very thick accent? What is he reading?

It’s not a guy at the end of Ummagumma reading poetry —the famous spoken- word section is usually the track “Several Species of Small Furry Animals Gathered Together in a Cave and Grooving with a Pict,” and the “thick accent” is Roger Waters doing a Scottish-style Pictish voice.

What he’s “reading” is essentially a comic, faux-ancient monologue rather than a real poem, and the words are mostly gibberish-like performance speech built to sound rustic and eccentric.

What to listen for

• The voice is part of the studio track, not a separate person at the end of the album.

• It’s designed as a character performance, not a straight reading of an existing poem.

• The effect is intentionally absurd and theatrical, which is why it stands out so much.

Plain answer

If you mean the odd spoken section people remember from the album, it’s Roger Waters , and he’s performing a made-up “Pict” rant rather than reading a known poem.

TL;DR: Roger Waters; not a real poem, more a surreal spoken-character bit.