Szemerényi's law

Szemerényi's law (or Szemerényi's lengthening) is both a sound change and a synchronic phonological rule that operated during an early stage of the Proto-Indo-European language (PIE). Though its effects are evident in many reconstructed as well as attested forms, it did not operate in late PIE, having become morphologized (with exceptions reconstructible via the comparative method). It is named for Hungarian linguist Oswald Szemerényi.

Overview

The rule deleted coda fricatives *s or laryngeals *h₁, *h₂ or *h₃ (cover symbol *H), with compensatory lengthening occurring in a word-final position. In other words:

*/-VRs/, */-VRH/ > *-VːR

*/-VRH-/ > *-VR- (no examples of s-deletion can be reconstructed for PIE)

Morphological effects

The law affected the nominative singular forms of any masculine and feminine nouns whose stem ended in a resonant, which were numerous:

with CL:

PIE */ph₂térs/ "father" > *ph₂tḗr (Ancient Greek patḗr, Sanskrit pitā́)
PIE */ǵénh₁tors/ "parent" > *ǵénh₁tōr (Ancient Greek genétōr, Latin genitor)
PIE */dʰéǵʰoms/ "earth" > *dʰéǵʰōm (Ancient Greek khthṓn, Sanskrit kṣa, Hittite te-e-kán)

The rule also affected the nominative-accusative forms of neuter plural/collective nouns, which ended in *-h₂:

PIE */ǵénh₁monh₂/ "seeds" > */ǵénh₁mōn/ > *ǵénh₁mō (on n-deletion see below)

Also in the third-person plural perfect ending:

PIE */-ers/ (the third-person plural perfect ending) > *-ēr (Latin ēr-e, Hittite -er, -ir)

without CL:

PIE */werh₁-dʰh₁-o-/ "word" > *werdʰh₁o- (Latin verbum)

Further effects

According to another synchronic PIE phonological rule, word-final *n was deleted after *ō which most usually resulted from the operation of Szemerényi's law:

PIE */ḱwóns/ "dog" > */ḱwṓn/ > *ḱwṓ (Sanskrit ś(u)vā́, Old Irish cú)

The PIE reconstruction for "heart" is the single instance where *d is deleted after *r, with compensatory lengthening of the preceding vowel. It is not clear whether this is an isolated example, or a part of a broader process such as Szemerényi's law.

PIE */ḱérd/ "heart" > *ḱḗr (Ancient Greek kêr, Hittite ker)

Morphologization of the law

The resulting long vowels had already begun in PIE to spread analogically to other nominative singular forms in which they were not phonologically justified by the law (e.g. PIE *pṓds 'foot'). The word-final sonorants other than *-n were sometimes dropped as well, which demonstrates that this law was already morphologized in the period of "PIE proper", and the long vowel produced was no longer synchronically viewed as the outcome of a process of fricative deletion. Exceptions to Szemerényi's law are found in word-final:

PIE */gʷénh₂s/ "woman" > *gʷḗn (Old Irish bé) but also *gʷénh₂ (Sanskrit jáni)
PIE *wih₁roms "men" (and not **wih₁rōm) > Gothic wairans
PIE *sals "salt" (and not **sāl) > Ancient Greek háls

as well as medial positions:

PIE *gen- > Sanskrit janman, PIE *genh₁- > Sanskrit jánitrī

The forms without a laryngeal are considered to be more archaic and were likely to have been lexicalized at a later stage of PIE.

References

Trask, Robert Lawrence (2000). The Dictionary of Historical and Comparative Linguistics. Routledge. ISBN 1-57958-218-4.
Benjamin W. Fortson (2004). Indo-European Language and Culture: An Introduction. Blackwell Publishing. p. 64. ISBN 1-4051-0316-7.
Byrd, Andrew M. (2010), Reconstructing Indo-European Syllabifiation (PDF), pp. 91–94