Our cats know their names.
As do mine. Caelan doesn’t even flinch if I’m yelling at Tango.
Truth or Dare: How many of you sing “Soft Kitty” to your fuzzbutts?
(guiltily raises hand) (but only to Cheddar)
Are you sure? Maybe they are just reacting to your tone of voice when you call them?
Don’t get me wrong, I love my cats. But I’m not sure they have that kind of recognition.
Not sure if any serious studies have been done about this?
See @silenus’s post.
Our two know their names, we think, and they could be responding to tone of voice, but they always turn and look when we say their names in any tone.
The older one I sometimes call Big Guy instead of his given name, and he purrs when I say it. I sometimes call the younger one Little Guy, but he doesn’t have any visible response.
EC is EC-pie, EC-mop, EC-pot-pie, EC-rider, EC-bake-oven, Over-EC.
Tikva is Tikki, Kon-tiki, Tiki-pedia, Tiki-pop, Tiki-mop, and inexplicably: Tea-Pot.
The following names can apply to whichever cat (both are female) is handiest : Sweet-pie, Moppy-poppy, Banana-cream-pie, Moppy-poppy-banana-pop, Sweet-moppy, Moppy-poppy-princess, Princess-pie, and all variations thereof.
EC definitely knows her name and will come when I call her. Tikva seems to know her name because she will turn to look at me when I call her by name. But she is not inclined to actually do anything when she hears her name.
I had one cat who unambiguously knew his name. I’ve had several cats who didn’t know their names. I kinda think Pippin knows his name, but I’m not certain.

The Naming of Cats is a difficult matter,
Peter Ustinov in the movie Logans Run desribes the naming of cats.

I don’t think they process sounds in any way we might call language or names?
I don’t know whether all of them do; but some of them do.
Years ago, my sister and BIL acquired a cat. They tried out various names for a while; none of which seemed to fit. The cat ignored them. (ETA: Ignored the names; not the people.)
Then one day one of them said the word “banana” in the cat’s presence. Cat came running. Multiple experiments confirmed it: cat said her name was Banana. Or maybe Nana, though she was a kitten at the time of the naming. (Or maybe she wanted a banana; but that seems really unlikely, as she never showed any particular fondness for bananas.)
Mine all come to “kittykittykittykitty cat food!” But then, all the dogs have come to that, also.
They have names, and nicknames. Some of them have more nicknames than others. One acquired so many that it resulted in his being given another one: “The Cat With The Very Long Name.”

“goddamn cat”.
Sally is sometimes “Saldamit” when she’s earned that.
My last cat Tybalt only ever went by Tybalt. No nickname.
And he definitely knew it and responded to it.
We have Khoshekh and Roxy (named after Welcome to Nightvale and Homestuck characters, respectively). There is no doubt at all that they each know their name. Roxy somehow gets more nicknames than Khoshekh, and they include: Ms. Fluffy-Butt, Roxy-poxy, Roxalicious, and Roxanoodle. Khoshekh mainly gets his consonants drawn out, but he also gets called Long Boy, Mr. Squish, and Cuddle Punkin. Either of them can be called Kittlicious, Scooter Butt, or Kitty Bitty.
We are a very silly household when it comes to our cats.
Our two are almost always (90% of the time) called by their names, which are the same names they had before we took over from prior owners. My wife doesn’t believe in renaming pets, even the lizards, who I promise, don’t know their names.
Our friend who visits frequently just refers to them as “Orangey Spotty Kitty” and claims he can’t tell them apart. He can, he’s just being mean.
But they’re both kinda large and loud, so the secondary titles that are normally used are callbacks to a forgotten (and for good reason) beverage!
Moxie Energy Thunder and Moxie Energy Explosion. Yes. Those are names of actual beverage from the Moxie company in the semi-recent past. Sometimes marketed (and thus the cats called out to) with “Zero Carb” As part of the drink names. Or just shortened to Thunder and Explosion. Often while laugh-cursing.
I could see calling them Red Alert and Brown Bomber.
My cat is named Tibbs but since he’s dumber than a salad bar I usually just call him “stupid.”

just shortened to Thunder and Explosion
Two of mine were sometimes referred to as “Chaos and Destruction!” I never tried to figure out which one was Chaos and which one was Destruction; they were usually both in it together.
One of the current ones is in process of acquiring the nickname "In-The Way-Of-The-Keyboard Cat.’
I also sometimes respond to the presence of a cat by saying “You’re a cat!”; though I suspect that they already know that.
Rocky = Rocky Rococo, Captain America, the most beta cat ever
Mia = Mia mine, sweetie, Mia moo
Pitch Black = Pitch-a-doos, Baby Boo, Handsome Prince, Boofriend
Helmut von Helmet = The Dude, Dude, Speedy boy
Mercedes Marie = Queen of Everything, MomCat, Noisy Girl
Lon Chaney, Jr. = Scaredy Cat, Quiet Boy, Lon Boy, Bestest Boy
Duke is Mr. Kitty, Silly Boy, Coo Coo, and Mr. Half-second (because that’s his attention span)
Ella is Kitzel, Oopie-Boopie, and Little Girl
My dad calls the neighbor cat “Furball”
Regardless of their real names, my Dad always referred to whatever cat we had as “Stupid Minou”. They didn’t seem to mind.