Dogs Can Tell Difference Between Owner's Native Language, Foreign Languages, Says Study

Dog brains have the capacity to detect speech and distinguish between different languages, according to a study published in December.

Since family dogs are exposed to a continuous flow of human speech throughout their lives, researchers from the Department of Ethology at the Institute of Biology at Eötvös Loránd University in Budapest, Hungary, decided to study the extent of their abilities due to speech perception being unknown.

For example, if a family moved from the United States to China, would the dog be able to understand the Chinese language?

Laura Cuaya, one of the study's main authors, said the study was prompted by her own experiences. As told in EurekAlert! she moved from Mexico to Hungary to join university for postdoctoral research and her dog, Kun-kun, joined her.

"Before, I had only talked to him in Spanish," Cuaya said. "So, I was wondering whether Kun-kun noticed that people in Budapest spoke a different language, Hungarian. We know that people, even preverbal human infants, notice the difference. But maybe dogs do not bother."

Researchers used functional magnetic resonance imaging (MRI) to test speech detection and language representation in dogs' brains, with dogs listening to natural speech and scrambled speech in familiar and unfamiliar languages.

"Speech scrambling distorts auditory regularities specific to speech and to a given language but keeps spectral voice cues intact," the study stated. "We hypothesized that if dogs can extract auditory regularities of speech, and of a familiar language, then there will be distinct patterns of brain activity for natural speech vs. scrambled speech, and also for familiar vs. unfamiliar language."

To test dog brains' capacity for speech detection and language representation, dogs were presented with an algorithm of natural and scrambled speech in the Hungarian and Spanish languages.

A total of 18 adult family dogs participated, including nine females aged between 3- and 11-years-old with a mean age of about 6.6 years. The dog breeds included five golden retrievers, six border collies, two Australian shepherds, one labradoodle, one cocker spaniel and three mixed breeds.

Hungarian was the language spoken around 16 dogs, while Spanish was spoken around two dogs. The other language, or "unfamiliar language," was unknown to all dogs.

Also, 16 human adults with a mean age of about 30.9 years participated in an online survey to rate the naturalness of the stimuli. The adults had no knowledge of either the Hungarian or Spanish languages. Their native languages were as follows: four French, three English, two Hebrew, two Italian, two Polish, one German, one Portuguese, and one Swedish.

Researchers said distinct activity patterns were found for the two languages, Hungarian and Spanish, in dogs' brains "with a greater difference in responses to the familiar and unfamiliar languages in older dogs, indicating a role for the amount of language exposure."

Raul-Hernandez Perez, a study co-author, said that "whereas human brains are specially tuned to speech, dog brains may simply detect the naturalness of the sound."

"It is exciting because it reveals that the capacity to learn about the regularities of a language is not uniquely human," added study senior author Attila Andics. "Still, we do not know whether this capacity is dogs' specialty or general among non-human species.

"Indeed, it is possible that the brain changes from the tens of thousand years that dogs have been living with humans have made them better language listeners, but this is not necessarily the case."

Future studies need to be conducted to better grasp the language barrier between humans and dogs, he said.