Īll Indo-European languages are descended from a single prehistoric language, linguistically reconstructed as Proto-Indo-European, spoken sometime in the Neolithic to Early Bronze Age. There are about 445 living Indo-European languages, according to an estimate by Ethnologue, with over two-thirds (313) of them belonging to the Indo-Iranian branch. In total, 46 percent of the world's population (3.2 billion people) speaks an Indo-European language as a first language - by far the highest of any language family. Today, the individual Indo-European languages with the most native speakers are English, Hindi–Urdu, Spanish, Bengali, French, Russian, Portuguese, German, and Punjabi, each with over 100 million native speakers many others are small and in danger of extinction. The Indo-European family is divided into several branches or sub-families, of which there are eight groups with languages still alive today: Albanian, Armenian, Balto-Slavic, Celtic, Germanic, Hellenic, Indo-Iranian, and Italic and another nine subdivisions that are now extinct. Some European languages of this family, English, French, Portuguese, Russian, Dutch, and Spanish, have expanded through colonialism in the modern period and are now spoken across several continents.

The Indo-European languages are a language family native to the overwhelming majority of Europe, the Iranian plateau, and the northern Indian subcontinent.

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