Proto-Indo-European numerals

The numerals and derived numbers of the Proto-Indo-European language (PIE) have been reconstructed by modern linguists based on similarities found across all Indo-European languages. The following article lists and discusses their hypothesized forms.

Cardinal numbers
The cardinal numbers are reconstructed as follows: Other reconstructions typically differ only slightly from Beekes and Sihler. A nineteenth-century reconstruction (by Brugmann) for thousand is. See also Fortson 2004.

The elements (in the numerals "twenty" to "ninety") and  (in "hundred") are reconstructed on the assumption that these numerals are derivatives of *deḱm̥(t) "ten".

Lehmann believes that the numbers greater than ten were constructed separately in the dialect groups and that originally meant "a large number" rather than specifically "one hundred."

Gender of numerals
The numbers three and four had feminine forms with the suffix, reconstructed as and , respectively.

Numerals as prefixes
Special forms of the numerals were used as prefixes, usually to form bahuvrihis (like five-fingered in English):

Ordinal numbers
The ordinal numbers are difficult to reconstruct due to their significant variation in the daughter languages. The following reconstructions are tentative:


 * "first" is formed with (related to some adverbs meaning "forth, forward, front" and to the particle  "forth", thus originally meaning "foremost" or similar) plus various suffixes like  (cf. Latin primus, Russian perv-).
 * "second": The daughter languages use a wide range of expressions, often unrelated to the word for "two" (including Latin and English), so that no PIE form can be reconstructed. A number of languages use the form derived from *h₂enteros meaning "the other [of two]" (cf. OCS vĭtorŭ, Lithuanian añtras, Old Icelandic annarr, modern Icelandic  annar )
 * "third" to "sixth" were formed from the cardinals plus the suffix : "third" etc.
 * "seventh" to "tenth" were formed by adding the thematic vowel to the cardinal:  "eighth" etc.

The cardinals ending in a syllabic nasal (seven, nine, ten) inserted a second nasal before the thematic vowel, resulting in the suffixes and. These and the suffix spread to neighbouring ordinals, seen for example in Vedic aṣṭamá- "eighth" and Lithuanian deviñtas "ninth".

Reflexes
Reflexes, or descendants of the PIE reconstructed forms in its daughter languages, include the following.

Reflexes of the cardinal numbers
In the following languages, reflexes separated by slashes mean:
 * Albanian: Tosk Albanian / Gheg Albanian
 * Armenian: Classical Armenian / Eastern Armenian / Western Armenian
 * English: Old English / Modern English
 * German: Old High German / New High German
 * Irish: Old Irish / Modern Irish
 * Ossetic: Iron / Digor
 * Persian: Old Persian / Modern Persian
 * Tocharian: Tocharian A / Tocharian B