I'm getting flashbacks of The Promised Neverland Season 2. They can't mess it up that bad, right?
The demons talk to each other so language is used for actual communication, not just manipulative mimicry. Also beasts don't use language, but do have emotions and sociality. Frieren described demons like how Mira described politicians.
Politicians aren't capable of referring to objects or concepts because their words have no meaning. They are simply utterances calculated to cause you to vote for them. If they could screech white noise at you that triggers your neurons to fire in a way that makes your hand fill out the ballot favorably, they would do that instead of presenting a policy or hosting debates. And if they seem to talk about Al, that is a statement about the listener not the speaker.
I read the first couple volumes of the manga after watching the anime. If you love the anime, then the manga is worth reading. I would certainly recommend reading the manga over watching the anime a 2nd time.
The anime was very faithful to the manga. There were some minor scenes that didn't get adapted, but I think they added value in the manga. There are some lines and dialogs that I thought were better written/translated in the manga. I really liked the translation notes at the end of each volume.