An odd or confusing sound or speech can be described as gibber.
Gibbering usually refers to speaking nonsense or mumbling incomprehensible words. But it can also mean making strange noises, like a mix of talk and sounds that don't make sense together. This can happen when someone's trying to communicate but their words are jumbled up or unclear. For example, if you're talking on the phone and there's a lot of background noise, your friend might say you sound like you're gibbering into the receiver.
To jabber, talk rapidly and unintelligibly or incoherently.
Manic, meaningless speech; babble.
Prone to meaningless vocalization, especially excited and confused utterances, like a beast or monster.
