Some scientists in Sweden will try to examine cat owners from different parts of their country to see if cats develop an "accent" similar to their owners' when the owners talk to them. The most prominent example notwithstanding, people from different parts of Sweden speak their tongue with different accents, much as people from different parts of the United States speak English with different accents. Except for Donald Trump, who technically does not speak with a particular accent but instead lies with one.
Studying the kind of ways cats vocalize with their humans -- apparently we are not nearly smart enough to understand their body language and scent cues -- could lead the researchers to understand what the different vocalizations might mean. There may be something to this. The cat who allowed me to live under her roof would often burrow underneath the comforter on the bed to create a lump in the middle of the bed that I would find when I returned home. Touching the lump brought a meow with a distinctly interrogative pitch change at the end -- as if my intrusion was being answered with, "Yes? Why did you disturb my slumber, clumsy food slave?"
The headline National Geographic puts on the story is kind of amusing. "What are cats trying to tell us?" it asks, as though we do not know the answer. Cats are almost always telling us that they can see almost no reason on earth not to rip out the throat of every human being on the planet except that humans can scratch that one spot between their eyes that they can't reach themselves. And that if we are not careful, they will forget that reason and although they would regret not being scratched between the eyes they will not be a bit sorry for exterminating us. Just as soon as they take a nap.