Languages spoken by billions of people across both Europe and Asia may have all descended from the same ancient tongue used in southern Europe at the end of the last ice age, according to a new study led by Reading University’s Mark Pagel.

Published in the journal Proceedings of the National Academy of Sciences of the United States of America, the report uses statistical models to predict that certain words would have changed so slowly over time that they would have retained traces of their ancestry for up to 10,000 years.

Such words, in turn, point to the existence of a linguistic super-family tree that unites seven major language families of Eurasia, according to the researchers.

Previously, linguistics relied on studying shared sounds among words in order to identify those that likely derive from the same ancestral words.

However, this model has the inherit flaw that some words, like team and cream, sound similar simply by accident.

In order to address this issue, Pagel and his team demonstrated how a subset of words frequently used in everyday speech are more likely to last over a long period of time.

Based on this method, the team then predicted words likely to have shared sounds, thus giving greater confidence that when such sound similarities were uncovered, they were not merely the result of chance.

“The way in which we use a certain set of words in everyday speech is something common to all human languages,” Pagel said in a press release issued by Reading University. For this reason, he said he and his team found that numerals, pronouns and special adverbs were replaced far more slowly, ultimately exhibiting a linguistic half-life of once every 10,000 years, if not more.

“As a rule of thumb, words used more than about once per thousand in everyday speech were seven to ten times more likely to show deep ancestry in the Eurasian super-family,” Pagel said.

In fact, based on the research conducted by him and his team, Pagel believes that people living 15,000 years ago might have used forms of the words I, you, we, man and bark that in some cases would still be recognized today.

Ultimately, as The Guardian reports Pagel as saying, such evidence suggests that everyone in Eurasia "can trace their linguistic ancestry back to a group, or groups, of people living around 15,000 years ago, probably in southern Europe, as the ice sheets were retreating."