# Proto-Indo-European **Domain:** Linguistics / Prehistory **Doc Type:** Concept Node **Maturity:** Developed ## Definition **Proto-Indo-European** is the reconstructed common ancestor of the Indo-European languages, a family that includes English, Latin, Greek, Sanskrit, Persian, Russian, and hundreds more. No written record of it survives; linguists rebuild its words and grammar by comparing their descendants through regular [[wiki/Sound Change|sound changes]]. It was probably spoken several thousand years ago, with estimates commonly placed between about 4500 and 2500 BCE. In 1786 Sir William Jones observed that Sanskrit, Greek, and Latin share too much to be coincidence and must spring from a common source. Many English words still carry its roots, such as *kaid-* "to strike" behind Latin *caedere* and *leg-* "to collect, speak" behind *logos* and *lexicon*. ## Relationships - **Mechanisms:** [[wiki/Ablaut|Ablaut]] · [[wiki/Grimm's Law|Grimm's Law]] · [[wiki/Sound Change|Sound Change]]. - **Field:** [[wiki/Etymology|Etymology]]. - **Practice:** [[wiki/Phonetic Etymology|Phonetic Etymology]]. - **Corpus project:** [[projects/Ten Years Building a Symbolic Language Engine|Ten Years Building a Symbolic Language Engine]], Bryant McGill's symbolic language engine, built from 1994 into the mid-2000s, with its phonological engine, sound indexes, and lexical knowledge graph. ## Sources - Calvert Watkins, *The American Heritage Dictionary of Indo-European Roots*, 3rd ed. (2011). - J. P. Mallory and D. Q. Adams, *The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World* (Oxford University Press, 2006). ## See Also [[wiki/Etymology|Etymology]] · [[wiki/Lexicon|Lexicon]]