General knowledge · Words & language
Proposed 1786; ancestor spoken c. 4500–2500 BC
Historical linguistics — the largest family of languages on earth
The family that takes in almost all the languages of Europe, the Iranian plateau and northern India, from English and Irish to Greek, Russian, Persian and Hindi. Its existence was announced in Calcutta in 1786 by Sir William Jones, who noticed that Sanskrit shared with Greek and Latin a resemblance too strong to be accident and inferred a common source that no longer survived. That source, Proto-Indo-European, was never written down: every word of it is a reconstruction, marked with an asterisk. About half the people alive speak one of its descendants.
Sir William Jones told the Asiatic Society in Calcutta that Sanskrit bore to Greek and Latin an affinity stronger than could possibly have been produced by accident (1786)
The Third Anniversary Discourse — the founding statement of comparative philology
Hittite, recovered from clay tablets in central Turkey and deciphered in 1915, turned out to be the earliest attested branch (1915)
Bedřich Hrozný's decipherment; the Anatolian branch is now reckoned the first to split away
August Schleicher wrote a fable about a sheep and some horses in a language nobody had ever spoken (1868)
Schleicher's fable, the first attempt at connected text in the reconstructed parent
Marija Gimbutas put the homeland on the Pontic–Caspian steppe; Colin Renfrew put it in Anatolia with the first farmers
The Kurgan hypothesis against the Anatolian hypothesis; ancient DNA has since favoured the steppe
Latin pater, Sanskrit pitar and Old English fæder all go back to a single word written with an asterisk in front of it
The asterisk marks a form as reconstructed rather than attested
Tocharian, found in Buddhist manuscripts in the Tarim Basin, falls in the western half of the hundred-word division despite being the easternmost branch
A long-standing puzzle for the centum/satem split
Armenian and Albanian each make up an entire branch of the family on their own
Single-language branches with no close surviving relatives
Thomas Young supplied the English name for the family in a review of 1813; German scholarship long preferred a name ending in -germanisch (1813)
Indogermanisch is still the usual German term