I do this all the time, heh. I ask my hamsters what they're up to, before I pick them up I ask if they want to come out, I gently tell them off if they do silly things during playtime. I know their intelligence level is far too low to understand or pick out individual words but I think the soft, gentle tone of voice helps them to trust me and feel safe. I don't think their vision is great either so talking to them probably gives them just a little more sensory information about the huge human creature looming over him?
When I first had the Syrian hamster I'd been told he was female and old enough to be physically mature (he came from a rescue). I used to call him Princess and say really girly things to him. When he actually got a bit older and turned out to be very obviously a boy I found my tone changing completely, I hadn't realised I was automatically adjusting my tone because of the gender of my hamster... not very politically correct even though he'd never realise haha! Stern word to self on not making assumptions and I don't change my tone for male/female animals now!