Note: I’ll use “Language” (capital L) to refer to the human ability, and “language” (minuscule l) to refer to specific implementations of that ability (stuff like Mandarin, Spanish, English, Arabic etc.)

Cool research, with shitty press coverage. The paper itself is rather careful on claiming that humans 135kya already had linguistic capacity; but the coverage is adding a lot of bullshit that leans into Proto-World quackery.

They reasoned that since all human languages likely have a common origin—as the researchers strongly think—the key question is how far back in time regional groups began spreading around the world.

This could be true but we should not assume that it is true, without ruling out other possibilities. In fact Miyagawa rather carefully hints those, when he says that “Language is both a cognitive system and a communication system,” […] “My guess is prior to 135,000 years ago, it did start out as a private cognitive system, but relatively quickly that turned into a communications system.”

“The logic is very simple,” says Shigeru Miyagawa, an MIT professor and co-author of a new paper summarizing the results. // "Every population branching across the globe has human language, and all languages are related."

Pick any creole of your choice. Focus on its syntax. Now look at the syntax of the lexifier languages. Done, the bolded statement is proven false.

Like many linguists, Miyagawa believes all human languages are demonstrably related to each other, something he has examined in his own work. For instance, in his 2010 book, “Why Agree? Why Move?” he analyzed previously unexplored similarities between English, Japanese, and some of the Bantu languages. There are more than 7,000 identified human languages around the globe.

Emphasis mine. To be frank this is smelling as fishy as those guys who claim to have reconstructed Proto-World from some random modern languages.

When you’re trying to understand the languages of the past, you don’t simply pick random modern languages and look for similarities. You pick the oldest varieties you have at your disposal, attested or reconstructed - because if they inherited something from their potential common ancestor, it’ll be easier to see, and you’ll get less noise being introduced by random mutations.

Try comparing Proto-Indo-European, Proto-Japonic and Proto-Niger-Congo instead.

“Human language is qualitatively different because there are two things, words and syntax, working together to create this very complex system,” Miyagawa says. “No other animal has a parallel structure in their communication system. And that gives us the ability to generate very sophisticated thoughts and to communicate them to others.”

You see the elements in the non-linguistic communication of other animals. For example, dolphins seem to have the ability to use some really primitive grammar. It is by no means Language proper but it shows that the difference is not qualitative - it’s quantitative.

EDIT: was meant as a reply.