prattle (on) about (someone or something)
To ramble, chatter, or babble about someone or something in an idle, meaningless, or incessant way. What on earth is he prattling on about now? Jeff's been prattling about some girl he met at camp over the summer. The date was pretty boring. She just prattled on about her dog for most of it.
prattle away (about someone or something)
To ramble, chatter, or babble (about someone or something) in an idle, meaningless, or incessant way. What on earth is he prattling away about now? Jeff's been prattling away about some girl he met at camp over the summer. The date was pretty boring. She just prattled away the whole evening, and I couldn't get a word in edgewise.