That doesn't prove they know words, I tend to pronounce my cats' names in exactly the same way each time. Maybe they're used to the notes I'm making, or my body language, or something else other than the word itself.

I don't know if my cat's ears will perk up if a stranger says their name, which is a test they have to pass to be considered to understand words.

I agree and then some. My cats know food, lunch, treat, toy, mouse(which is both a toy and the name of one of the cats), no, out(both outside and please leave the room), go home, up(get up on the bed or my lap), off(get off the dang counter/table for the 1 millionth time). They multiple name for themselves and the name of the other cats. They know that when I whistle I'm calling them.

Now if only they would do as well as hear more often...The Siamese talks back when I use words she doesn't want to hear and sometimes curses me.