In Danish we do the same thing:

temi pri = at handle om = to be about

In English you just use "to be" instead of a specific verb (like "at handle"). Literally, "at handle" means "to take action", but that still doesn't explain much to native English speakers.

"it takes action about" (yeah, sounds stupid)----> "the theme is about" ----> "it is about"

I'm going to repeat what others said: don't think Esperanto is a foreign-sounding equivalent of English, it's not.

Gaah! Alright, just because I've never used "temas" (with or without the "pri") doesn't mean that I'm even close to being in danger of thinking that eo is a directly coded form of English. I haven't used "temas" (with or without the "pri") because I have never thought to use it. There's LOTS of words I've never used. On the other hand, I have used many, many, eo constructions that have no direct English cognates, because they fit what I was trying to say.