I've read that an average dog possesses a vocabulary of 200-300 words, which is enough for him to have his own Twitter account. Most people won't buy their dogs a smartphone, though, so you don't see too many canines tweeting their friends unless they have access to a computer.

Here's an excerpt from a dog's wiki- dictionary of known words:

Sit (v): A word that means if you sit down your owner will give you a treat. Oddly, Sit works only some of the time. You can Sit all day while your owner is cooking tacos and he won't toss you one, even if you give him your most attentive expression. If, however, the owner starts saying "Sit!" and he has a dog treat in his hand, you're golden. Just make sure you pretend to take a long time to figure it out and you'll keep getting treats. The minute you give in and start doing it on command, though, he'll say "good dog" and there will be no treat involved. No one knows why people think that being told "good dog" is reward enough — would they go to work every day if instead of getting a paycheck, their bosses just said they were "good employees"?

Stay (v): This word makes no sense: It means that while your owners walk away, you're supposed to just sit there. This can't be right. Surely wherever they're going, the experience would be enhanced by having a dog present when they get there. If they don't want canine companionship, why did they get a dog? Also, there's no way to give a dog a treat if he Stays, because the owners have left. What good is a command if there is no treat involved? Worse, when Stay is over, the people will probably say "come," and then give you a treat. So at first, being with them is not good for a treat, and then all of a sudden it is. Probably if your owner tries to teach you to stay he is a mentally unbalanced person, so handle the situation however you need to in order to obtain a dog treat. (Once the reward for "Stay" migrates to "good dog" instead of "dog treat," we recommend you pretend you forgot what it means.)

Lie Down (v): First, some people say "lay down," which as any dog knows is bad grammar. Second, this one gets you a treat only after you've sprawled out on the floor, a position that makes it very difficult to chew. It's recommended you hold out for a treat before you Lie Down. Isn't that more convenient for everyone?

Bad Dog (n): The list of things you can do to qualify as a bad dog is so huge as to be completely bewildering. Your person left you lunch in the trash can when he went to work, so you helped yourself? Any reasonable dog would agree you showed excellent resourcefulness, but you guessed it, Bad Dog. Urinated in the house, which your person does all the time? Bad Dog. Barked at the mailman, who for all we know is on the verge of going postal? Bad Dog. You might as well give up trying to figure out what causes Bad Dog — you don't get a treat for being a bad dog; that's all you need to know.

Shake (v): Upon the command "shake," you're supposed to raise your paw and let your person grab it and drop it. It's a dumb way to earn a treat, in our opinion. If you show some initiative and, entirely on your own, paw your owner in the crotch, you probably won't get a treat (see Bad Dog).

Dinner (n): There simply isn't a finer word in the human vocabulary than "dinner." Most dogs try to explain this to their people by doing Sit, Lie down, Speak, Spin, Shake and Jump, but usually most people don't get it and serve dinner only once or twice a day.

Too bad they don't understand dog words.