The Indo-European language family comprises a vast number of languages and dialects spoken throughout the world today. All of these languages are descended from a common ancestor known as Proto-Indo-European, which scholars estimate was spoken about six thousand years ago. [1] This common ancestor has been reconstructed by historical linguists using the comparative method. [2] Although there is disagreement about the historical relationship of these languages to each other, this glossary uses the neo-traditional model of Indo-European phylogeny which states the main branches of the family are Albanian, Anatolian, Armenian, Balto-Slavic, Celtic, Germanic, Hellenic, Indo-Iranian, Italic, and Tocharian. [3]
This glossary provides a list of sound laws that have been formulated by linguists for the various Indo-European languages. Any sound laws which affects any of the major branches of the Indo-European family or more than one descendant language are included.