i know this probably doesnt count but ummm its cutest word ever. tell me you dont look at a little kitty-cat and go "oh! that is a little kitty-cat :3" (if you say you dont do that, youre lying)
It's the most fun English word for cat to say, cat is too neutral, kitty feels like it's not enough by itself, and kitten just applies to baby cats. Also it's a cute word