As different as the world’s languages may seem to the untrained ear, some concepts share the same sounds even in languages that are completely unrelated, a new study finds.

In a study spotted by Atlas Obscura and published in PNAS, a group of European researchers found that across nearly two-thirds of world languages, certain words retain some of the same sounds—whether they’re in Russian, Swahili, or French.

The researchers looked at word lists of about 100 basic vocabulary concepts (covering things like pronouns, names of body parts, verbs referring to motion, and nouns that describe natural phenomena), analyzing them to sound similarities. Some of the concepts included in the database of more than 6000 languages were blood, bone, leaf, mountain, sun, red, and kill.

Words that describe the properties of something, like “small” or “full,” showed particularly strong sound relationships between languages. Words for “small” typically have the “i” sound, and for “full,” the “p” or “b” sound. “Round” often has an “r” in it.

Body parts also had strong relationships to certain sounds. Words for “tongue” usually have an “l” or a “u,” and “nose” tends to involve nasal “n” sounds. The nursery terms for “mother” (think “mama”) tend to feature the “m” sound. One hypothesis for the latter concept—which, across many different languages, is not just a similar-sounding term but the exact same word—is that “mama” and its variants are related to the “mouth configuration of suckling babies or to the sounds feeding babies produce,” according to the study.

While this study can’t tell us why exactly these words tend to share the same sounds no matter where in the world they come from, the researchers hypothesize it could be that “the signals are due to factors common to our species, such as sound symbolism, iconicity, communicative pressures, or synesthesia.” These common sounds, they note, show some of the constraints on our abilities to communicate. “Despite the immense flexibility of the world’s languages,” they write, “some sound-meaning associations are preferred by culturally, historically, and geographically diverse human groups.”

[h/t Atlas Obscura]

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