Remember when only 20 years ago science didn't acknowledge that dogs and other non-human animals had conscious thought?
We dog-lovers knew they did of course, but science is always looking for evidence to challenge the Null Hypothesis. (Learn more about the Null Hypothesis if you really want to.)
Using a cleverly modified fMRI scanner and specially trained canine fMRI participants (I've blogged about this project elsewhere), scientists found solid evidence that dogs have the ability to distinguish words and the intonation of human speech through brain regions similar to those that humans use.
This is not to say that dogs use language, our species' complex and symbolic system of communication, but that they understand how humans use words to represent things.
Until scientists can coax a wild-type wolf or coyote into the fMRI scanner, and what's more enjoy it without fear, we won't know if this is an evolutionary strategy only dogs evolved with.
Science Daily included a nice summary of the science.