According to the 2009 Ethnologue estimate, the Indo-European languages family consists of about 440 languages and dialects, including major current languages of Europe, Iran, India, and also extinct Anatolian. Even though these languages are a great material for researchers, specialists have never agreed about their origin.
Some linguists propose that the first speakers of the mother language of Indo-European languages were the people who lived on the stepps above the Black Sea, 4000 years ago. Another theory suggests that The first speakers of this mother language were farmers in Anatolia, who helped expand the language through other farmers, approximately 9000 years ago.
In 2003, Russell Gray, a professor known for his studies on the Austronesian language family, and his student Quentin Atkinson declared that they have solved this controversy. The main idea before the publication of their research was that languages were pretty similar to genes, and that language evolution could be mapped in the format of a family tree. However, Gray and Atkinson proposed that the evolution of words was just like the evolution of species. The closeness of their sounds and meanings – in other words, their cognate – could be modelled like DNA sequences. Therefore, the rate at which the words changed could help determine the age at which Indo-European languages diverged form one another.
Neither Gray not Atkinson were linguists. This is why they used methods from evolutionary biology. They compared common words in 87 Indo-European languages, such as ‘mother’, ‘sky’, and ‘hunt’, to figure out the relation between language ‘species’. With their work, they traced the origins of Indo-European languages to 7800-9800 years ago, supporting the Anatolian hypothesis.