The Indo-Hittite hypothesis postulates a common predecessor for both the Anatolian languages and the other Indo-European languages, called Indi-Hittite or Indo-Anatolian.
the Indo-Hittite hypothesis is not widely accepted, and there is little to suggest that it is possible to reconstruct a proto-Indo-Hittite stage that differs substantially from what is already reconstructed for PIE.
These migrations ultimately seeded the cultures and languages of most of Europe, Greater Iran, and much of the Indian subcontinent (and subsequently resulted in the largest and most broadly spoken language family in the world).
Modern knowledge of these migrations is based on data from linguistics, archaeology, anthropology and genetics.
The following legend is given in the chronological order of the earliest surviving written attestations of each branch: The Indo-European languages constitute a family of several hundred related languages and dialects.
According to the widely accepted Kurgan hypothesis or Steppe theory, the Indo-European language and culture spread in several stages from the Proto-Indo-European Urheimat in the Eurasian Pontic steppes into Western Europe, Central and South Asia, through folk migrations and so-called elite recruitment.
This process started with the introduction of cattle at the Eurasian steppes around 5200 BCE, and the mobilisation of the steppe herder cultures with the introduction of wheeled wagons and horse-back riding, which led to a new kind of culture.
The existence of PIE was first postulated in the 18th century by Sir William Jones, who observed the similarities between Sanskrit, Ancient Greek, and Latin.
By the early 20th century, well-defined descriptions of PIE had been developed that are still accepted today (with some refinements).