Glossary of sound laws in the Indo-European languages

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. This common ancestor has been reconstructed by historical linguists using the comparative method. 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.

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.