

By the time the first written records appeared, Indo-European had already evolved into numerous languages spoken across much of Europe, South Asia, and part of Western Asia.

Written evidence of Indo-European appeared during the Bronze Age in the form of Mycenaean Greek and the Anatolian languages of Hittite and Luwian. The oldest records are isolated Hittite words and names - interspersed in texts that are otherwise in the unrelated Akkadian language, a Semitic language - found in texts of the Assyrian colony of Kültepe in eastern Anatolia dating to the 20th century BC. Although no older written records of the original Proto-Indo-European population remain, some aspects of their culture and their religion can be reconstructed from later evidence in the daughter cultures. The Indo-European family is significant to the field of historical linguistics as it possesses the second-longest recorded history of any known family, after the Afroasiatic family in the form of the pre-Arab Egyptian language and the Semitic languages.

The analysis of the family relationships between the Indo-European languages, and the reconstruction of their common source, was central to the development of the methodology of historical linguistics as an academic discipline in the 19th century. The Indo-European family is not known to be linked to any other language family through any more distant genetic relationship, although several disputed proposals to that effect have been made.
