The roots of the reconstructed Proto-Indo-European language (PIE) are basic morphemes carrying a lexical meaning. By addition of suffixes, they form stems, and by addition of endings, these form grammatically inflected words (nouns or verbs).

Except for a very few cases, the PIE root is fully characterized by its constituent consonants, while the vowel may alternate, a process called ablaut. The roots as a rule have a single syllabic core, and by ablaut may either be monosyllabic or unsyllabic.

Phonotactics

Basic root structure

The centre of a PIE root is the ablauting vowel (usually , perhaps sometimes ^[1] in the full grade). This vowel constitutes a sonority peak that is preceded and followed by a sequence of consonants with progressively decreasing sonority values (i.e., the sonority has to fall toward both edges of the root). The sonority hierarchy is as follows:^[2]

3. Plosives (see Proto-Indo-European phonology for a table of PIE plosives)

This gives the following root structure (with P being a plosive and \oslash an empty position):

^* \begin{Bmatrix} P \\ \oslash \end{Bmatrix} \begin{Bmatrix} w \\ m \\ \oslash \end{Bmatrix} \begin{Bmatrix} l \\ r \\ y \\ n \\ \oslash \end{Bmatrix} e \begin{Bmatrix} l \\ r \\ y \\ n \\ \oslash \end{Bmatrix} \begin{Bmatrix} w \\ m \\ \oslash \end{Bmatrix} \begin{Bmatrix} P \\ \oslash \end{Bmatrix}-

Note that after a vowel is often written , and after a vowel is often written . Thus, "to bind" and "to run" are allowed roots.^[3]

Other possible roots include "foot", "door" and "to moisten". Forbidden are structures like (wrong order of phonemes) and (two phonemes of the same group).

Additional phonemes

The remaining sounds, namely the laryngeals and the sibilant , can occupy almost any place in the hierarchy.^[2] is particularly common in initial position (see s-mobile).^[4]

Examples of such roots are "to fly", "to nourish" and "to stroke".

Restrictions on the plosives

A root cannot contain two plain voiced plosives (), nor can it contain a voiced aspirate and a voiceless plosive (), unless the latter occurs in a word-inital cluster together with an s-mobile (e.g. "to stiffen").^[4]

Restrictions on the number of phonemes

The vowel has to be preceded and followed by at least one consonant each. The maximum number of consonants seems to be five (as in "tight").^[4]

Early PIE scholars reconstructed a number of roots beginning or ending with a vowel. The latter type always had a long vowel ( "to put", "to grow", "to give"), while this restriction did not hold for vowel-initial roots ( "to eat", "front", "smell"). Laryngeal theory can explain this behaviour by reconstructing a laryngeal following the vowel (, , , resulting in a long vowel) or preceding it (, , , resulting in a short vowel). These reconstructions obey the mentioned rules.

Exceptions

It should be noted that some roots like "to sneeze" do not seem to follow these rules.^[2] This might be due to incomplete understanding of PIE phonotactics or to wrong reconstructions.

Root extensions

Root extensions are additions of one or two sounds, often plosives, to the end of a root which do not seem to change its meaning. For "to push, hit, thrust", we can reconstruct

• > Ancient Greek túkos "hammer"
• > English stoke (Germanic k goes back to PIE .)
• > Vedic tudáti "beats"

The source of these extensions is not known.^[4]

Notes

References

• Calvert Watkins, The American Heritage Dictionary of Indo-European roots: Second Edition, Houghton Mifflin, September 14, 2000 - ISBN 0-395-98610-9
• Carl Darling Buck, A dictionary of selected synonyms in the principal Indo-European languages: A contribution to the history of ideas, University of Chicago Press; Reprint edition (June 15, 1988) - ISBN 0-226-07937-6
• Karl Brugmann and Berthold Delbrück, Grundriß der vergleichenden Grammatik der indogermanischen Sprachen (1886-1916).
• Julius Pokorny, Indogermanisches etymologisches Wörterbuch (1959).
• Gerhard Köbler, Indogermanisches Wörterbuch (1980-2005).
• Helmut Rix et al., Lexikon der indogermanischen Verben (1998, 2001).
• Benjamin W. Fortson IV, Indo-European Language and Culture (2004).

External links

• American Heritage Indo-European Roots Index
• Vasmer's Etymological Dictionary of Russian language
• Index to the online version of Pokorny's PIE dictionary
• Wiktionary List of Proto-Indo-European Roots

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