|Sound change and alternation|
Quantitative metathesis (or transfer of quantity) is a specific form of metathesis or transposition (a sound change) involving quantity or vowel length. By this process, two vowels near each other – one long, one short – switch their lengths, so that the long one becomes short, and the short one becomes long.
In theory, the definition includes both
- long-short → short-long
- short-long → long-short,
but Ancient Greek, which the term was originally created to describe, displays only the former, since the process is part of long-vowel shortening.
This quantitative metathesis is more accurately described as one form of long-vowel shortening. Usually if quantitative metathesis affects a word, other kinds of shortening do as well, in the forms where quantitative metathesis cannot occur:
- ēwo → eō (quantitative metathesis)
- ēws → ews (shortening of long diphthong before consonant)
- ēi → ei (analogical shortening)
 First declension
- Πηλεΐδᾱο Pēleídāo → *Πηλεΐδηο *Pēleídēo → Πηλεΐδεω Pēleídeō (genitive singular; alternate form Πηληϊάδεω Pēlēiádeō in the first line of the Iliad)
The Attic genitive singular Πηλεΐδ-ου Pēleíd-ou uses a copy of the second-declension ending, which came from the same original form as the Thessalian Aeolic ending -oio (used in Homer) — o-syo, thematic vowel o and case-ending -syo). The Homeric form comes from the same case ending, with the first-declension pseudo-thematic vowel ā.
 Second declension
- Ionic ληός lēós (from λᾱϝός lāwós) → Attic λεώς leṓs "people"
- ληοί lēoí → λεῴ leōí (nominative plural)
But sometimes, when a long vowel occurs in the ending, ē is shortened to e without an accompanying lengthening of the vowel in the ending (but ou changes to ō to follow the other forms):
- ληοῦ lēoú → λεώ leṓ (genitive singular)
- ληῷ lēōî → λεῴ leōí (dative singular)
 Third declension
Some third-declension nouns had, in Proto-Indo-European, stems in -u or -i in zero-grade, -ew or -ey in short e-grade, and -ēw or -ēy in long ē-grade. Others had -āw with no variation in ablaut grade, which changed in some forms to ēw, by the Attic-Ionic ā → ē shift.
In many cases, the w or j was deleted, but sometimes it is preserved as the last element of a diphthong (-eus, -aus).
Stems with ē underwent shortening in Classical Attic-Ionic, but early forms with long ē are preserved in Homer to maintain the original meter. Some forms exemplify the quantitative-metathesis type of shortening:
- βασιλεύς basileús (shortened from *βασιλήϝς *basilḗws) "king"
- Homeric (early Attic-Ionic) βασιλῆος basilêos (from βασιλῆϝος basilêwos) → Classical Attic βασιλέως basiléōs (genitive singular)
- βασιλῆα basilêa → βασιλέᾱ basiléā (accusative singular)
- βασιλῆας basilêas → βασιλέᾱς basiléās (accusative plural)
- Attic ναῦς naûs "ship" (from *νᾱῦς *nāûs by shortening of ā: Latin nāv-is)
- νηός nēós (from *νᾱϝός *nāwós) → νεώς neṓs) (genitive singular)
- πόλις pólis "city"
- πόληος pólēos (from *πόληι̯ος *pólēyos) → πόλεως póleōs (genitive singular)
- ἄστυ ástu "town"
- *ἄστηος *ástēos (from *ϝάστηϝος *wástēwos) → ἄστεως ásteōs (genitive singular)
The accent of the genitive singular of the last two words violates the rules of accentuation. Normally the long vowel of the last syllable would force the accent forward to the second-to-last syllable, giving *πολέως *poléōs and *ἀστέως *astéōs, but instead the accent remains where it was before shortening.
Other forms of these nouns shorten ē to e, but because the vowel of the ending is long, no quantitative metathesis occurs:
- *βασιλήων *basilḗōn → βασιλέων basiléōn (genitive plural)
Some forms shorten ē to e before i according to the analogue of the other forms, but without lengthening the i:
- Homeric βασιλῆi basilêi → Attic βασιλεῖ basileî (dative singular)
Other forms involve no shortening, since they come from a short e-grade form of the stem. The accent of the genitive plural is sometimes irregular because it follows the analogue of the genitive singular:
- *πολέι̯-ων poléy-ōn → πόλεων póleōn (genitive plural — re-accented after genitive singular)
- *ϝαστέϝ-ων *wastéw-ōn → ἄστεων ásteōn (also re-accented)
- *τεθνηϝώτς tethnēwṓts → τεθνεώς tethneṓs "dead" (masculine nominative singular: perfect with stative meaning)
- *τεθνηϝότος *tethnēwótos → τεθνεῶτος tethneôtos (masculine/neuter genitive singular)
 See also
- Smyth, Greek Grammar, paragraph 34 on CCEL: transfer of quantity
- Smyth, paragraph 214 footnote: dialectal first-declension forms
- Πηλεύς. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at Perseus Project
- Paul Kiparsky, "Sonorant Clusters in Greek", Language, Vol. 43, No. 3, Part 1, pp. 619-635: Sep. 1967
- Smyth, paragraph 238 c: transfer of quantity and shortening in "Attic declension" forms
- λαός. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at Perseus Project (end of entry)
- Smyth, paragraph 39: shortening of long vowel before another long vowel
- Smyth, paragraph 270: stem variation of i, u-stems
- Smyth, paragraph 278: stem variation of au, eu, ou-stems
- Smyth, paragraph 40: shortening of long vowel before u, i, nasals, liquid + a consonant
- βασιλεύς. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at Perseus Project
- Smyth, paragraph 271: accent of genitive singular and plural of some i, u-stems
- Smyth, paragraph 163 a: exceptions to rules for antepenult accent
- Smyth, paragraph 301 c: masculine/neuter endings for perfect active participle