I think it’s good if you talk to them while your doing things in their enclosure, it can’t hurt and maybe they can feel the vibrations of your voice and get used to it? I don’t know but I like the thought and it’s what I do when I’m working in my guys enclosure.
"they can pick up sounds that fall in the frequency range between 200 and 600 Hz"..."the human voice starts at the top end of that scale -- 500 Hz, according to Cardiff School of Computer Science and Informatics"..."your chameleon can pick up at least some of the words you say"... https://animals.mom.com/can-chameleons-hear-talking-10364.html