My very old, 19 year old boy, is as deaf as a post now, so doesn't have an idea of how loud his voice is when he's hollering at/for me. When he's off somewhere in the house yowling, I have to track him down, in order to reassure him. The upside of his deafness, is that he now sleeps the sleep of the just, and it's lovely to see him so undisturbed.
My 6 year old girl is Spanish, and we frequently converse in her language. She is the scarediest cat ever, and I wish I knew why. She makes the most adorable little warble sound and her purr is so low, it's just about audible.
My other girl is nearly 3 and is on a mission to take over the household. So much so, that she has to be kept separate from my other 2, which is a shame. She constantly demands treats and has a screamy kind of meow that breaks me down every time.
A cat will recognise your voice before recognising your body, so I always speak out to my scaredy cat when I'm approaching her from a place from where she can't see me coming.
Such fun!