The idea of all languages having a common forebear is not a new idea (the Tower of Babel for example and has been considered by linguistic researchers for decades) but new research suggests that many languages spoken by people in Europe, Asia and America descend from a common language spoken during the Ice Ages 15,000 years ago.
Researchers have long used cognates (words that have a common etymological origin) as a kind of lingustic "DNA" to reconstruct ancient proto-words and have traced some common words back as far as 9000 years ago. This ancient Indo-European language later gave rise to languages like English, French, Hindi and Russian.
This is pretty much accepted, what is more controversial is tracing language back further. Some say this is too far back to meaningfully trace language roots as too many words would have changed over time. However researchers at Reading University have used statistical modelling to identify very common words have survived for thousands of years and which are shared across a number of ancient proto-languages across Europe and Asia linking Indo-European to other language groups like Altaic and Inuit-Yupik. Words which have survived include "I" and "We" (which might be no surprise) but also common are words like "bark" and "ashes". This is more surprising but then we should consider the cultural importance of such words to humans in the Stone Age.