There’s a reason that you talk to dogs like they understand: They kinda do. Dogs’ brains process speech just like human brains do.
Researchers in Hungary put a dozen very cooperative golden retrievers, border collies, and a German shepherd in an fMRI machine, and murmured praise and unknown words (“such,” “as if,” “yet”) in varying intonations. They found that the dogs’ brains responded to speech just like a human brain would, processing emotional meaning separately from word meaning.
In both dogs and humans, ancient, subcortical parts of the brain process intonations, while higher, cortical parts of the brain process word meanings. The researchers note that this is telling about the evolution of speech, which likely developed from emotionally loaded intonations.