I grew up with a dog, and I know that dogs don’t really “understand” human speech, but they can learn their name and commands like, “No teeth!” and “Sit!” and “No!”
Last weekend, I got my first cat (mandatory cat pictures). She doesn’t respond to her name, and she ignores “no.”
So, do cats not understand that they’re being scolded, or do they just not care? Can they learn, like dogs can? If they don’t understand what “No!” means, how do you teach them to not do things?
Cats understand. They just don’t care.
I’ve known plenty of cats who demonstrably understood their name (at least understood that it meant “Hey You! Attention!” or “Come Over Here!”)
I believe they can understand speech. Cats are trainable to do a variety of things and respond to verbal commands.
I think the issue is they are by nature not as “programmed” as dogs to accept training easily. I know for a fact my cats know their names. If I call one name or another the appropriate cat will usually turn its head to look at me to see what it is I am on about. The other cat ignores the name completely unless I call her name then she responds similarly. Neither will come when I call…just acknowledge they heard it.
My cats understand stuff. Sometimes they respond.
I’m giving 3x daily drops in Glaucoma Cat’s eye. I say, “C’mere big fella…lemme poke you in the eye.” He rarely responds.
But if I say “C’mere big fella, come cuddle with mommy” he’ll hop right up on my lap.
Another one likes to go for a walk on Mr. K’s shoulder. If we say “Wanna go for a walk?” she’ll hop up on the fridge (access point for the walk).
We have another one who just loves being told it’s her birthday! She gets all bonky and rolly when we say it.
That’s about what I figured. I think she’s not a pet so much as a third roommate who doesn’t pay rent. 
My cat understands he is doing something wrong if I do the “Tssst” sound. Typically he won’t stop though. I have to get up and approach him before he runs off. About 50 percent of the time, after he runs off he will hide and then attack my feet.
He’s an ass like that.
Yeah, they’re like a stubborn, opinionated dog - a whole species of Jack Russell terriers. Edison knows who we’re talking about when we call him Fattles, too.
I had “Puppy-Cat” a Siamese who was raised by a mother dog after his own mother rejected him. He understand “retrieve” and would go get his ball so I could throw it and he could bring it back. When I said “Go Out” he would go to the front door and let me put his leash on. “Bedtime” and he would run to his floormat which was beside my floormat.
I miss Puppy-Cat.
My family had a cat who was so attentive to our talking about food that we had to be guarded with words like “cheese” and “treat” because, once he heard one of the magic words, he’d get so frantically hyperactive and bouncing-off-the-walls ecstatic that we’d have little choice but to go ahead and give him something.
Then my Mom got the idea of *spelling out * the magic words, so “treat” became “T-R-E-A-T”. He twigged to it immediately.
My sorely missed Lenny responded to a variety of verbal commands and learned several of the standard “dog tricks” such as “sit”, “beg”, “speak”, and “fetch” (as “go get the birdy”).
He of course responded best to his name and reward words: “suppertime”, “cookie”, and “Kill it! Kill it!” (which referred to flies trapped by the window. He loved killing flies.)
ETA: He would also often only very begrudgingly do “sit”, “beg” and “speak”. If you weren’t waving a slice of bacon, he’d probably ignore you. He understood the commands and would do them, but only if there was a worthwhile reward.
ETA 2: My other cat, Squiggy, seems too stupid to understand most commands and only seems to respond to his name and “suppertime” (and that’s only because Lenny used to).
A fundamental difference between dogs and cats.
Catch a dog in the act of cleaning out the kitchen trash or giving your dining room table a leg-ectomy. Shout at dog, repeatedly call it bad, swat it with a rolled up newspaper. Dog says to itself “hmmm, I have displeased the master. I should not do that again.”
Catch a cat in the act of transforming your shower curtain into a hanging fringe. Shout at cat, repeatedly call it bad, give it a quick blast of cold water from the hand held shower nozzle. Cat says to itself “hmmm, I have displeased my servant. I should only redecorate the bathroom when he is not around.”
Tsssting, Tsssting, one, two, three…
You have WAY to much time on your hands.
Our younger cat Phoenix definitely understands “No.” She loves to intimidate our older cat, but if I see Phoenix getting ready to pounce, I will say “no, no, no” and she understands that it means trouble for her if she carries out her nefarious plans. The older cat also seems to understand that she’s not getting in trouble, Phoenix is. They also both respond when we call their names. That doesn’t mean that either of them are completely obedient, just that they recognize the speech.
Pot, Kettle calling…
Cat fight! Cat fight!
I can deliver the line with any intonation or accent, but when my dog hears, “Shall we go out then?”, he knows exactly what I am saying, and will go and get his ball, or whatever he wants to take with him.
Spray bottle. It’s the only thing that actually works for our three, except for actually getting up and chasing them away from the victim of their current malice.
When I was a kid, my family owned a cat who knew certain words, and like other posters have said, typically it seems like they only learn and/or react to words that have direct meaning for them. So they may well understand what you mean if you teach them what “sit” is, but if they don’t want to sit, they might ignore you.
You could look straight at the cat (to avoid other cues like glancing at the item) and ask “Where’s the _______” and she’d go look. “Treat” would send her to the kitchen to pace under the counter that held the treat containers. “Mouse” would make her run to a baseboard that once had a mousehole in it, and which had been covered over with a new baseboard but still had hints of mouse activity and sound. “Bird” would have her running to a window, typically the bathroom window in the back since that had a good view of the bird feeder. Of course we’d accidentally trained her to learn those words in the usual fashion, talking about “treat” when giving her one, asking if she saw a “bird” when she was crouched in the window, eyeing the feeder’s occupants, etc.
(On a side note, it seems like ferrets can learn words similarly. I even taught one of our ferrets to sit up on the command. Since they have teeny little attention spans, I only ever bothered with the one. 
)
And if you say “No!” while squirting them, they rapidly learn that “No!” means imminent water attack and they’ll run for the hills. Effective.
Gary Larson did a pair of Far Side cartoons on this topic.
[What we say to dogs
What we say to cats](http://healingmagichands.wordpress.com/2007/12/18/some-favorite-cartoons/)
(scroll about halfway down the page for both cartoons, or search for the word “pair”)