Dr. Stanley Coren, a psychologist at the University of British Columbia, has concluded:

dogs understand 165 words, signs and signals . . . those in the top 20 per cent of intelligence can learn 250 words.

Many dog owners and trainers agree that they can communicate with their dogs in language beyond simple commands.

A golden retriever owner says:

When you tell him to go get his Kong, he brings his Kong – not his play shoe or sock or stuffed toy . . . (He also understands that when we tell him to go get his play shoe, sock or stuffed toy, he brings those.)

Jenny Pavlovic, author of 8 State Hurricane Kate, says her herding dogs know:

“Go by” means to go clockwise and “Away” means to go counterclockwise. They do this with just verbal input, and no physical direction.

Dan Laxton, whose business uses border collies to remove geese humanely and who volunteers with search and rescue dogs, says they can understand the same word to mean different things at different times:

Bed said during the day means get in the kennel. Bed at night means go upstairs to the bedroom.

Coren says breeding dogs for specific jobs has brought them to this level.

Jack Russell Terriers, originally hunting dogs, are known to be very intelligent. Judi Perkins, who once owned a JRT, can list not only many words, but entire phrases he understood. For example:

“Let’s go upstairs “(I could stand still and he’d go upstairs, get to the landing, and turn around like “are you coming?” – as opposed to “Upstairs”, when I told him where something was and he’d just go get it)

Alicia Moore says her standard poodle:

understands and can differentiate between “Go get your toy” and “Where’s your boy?” even if I use the same tone and inflection.

Dogs can do math, too – but that’s another story.