Kʷetwóres rule

The so-called PIE|kʷetwóres rule of Proto-Indo-European (PIE) has been observed by earlier scholars, but has only recently attracted enough attention to be named, probably first by Helmut Rix in 1985. It is a sound law of PIE accent, stating that in a word of three syllables "é-o-X" the accent will be moved to the penultimate, "e-ó-X". Examples include
*PIE|kʷetwóres < PIE|kʷétwores "four"
*singular accusatives,
**of r-stems, PIE|swes-ór-m̥ < PIE|swés-or-m̥ "sister" Acc. Sg.
**of r/n-heteroclitica, PIE|ǵʰes-ór-m̥ < PIE|ǵʰés-or-m̥ "hand" Acc. Sg.
**of s-stems, PIE|h₂aws-ós-m̥ < PIE|h₂éws-os-m̥ "Hausos" (Vedic Sanskrit Unicode|uṣā́sam")The rule is fed by an assumed earlier sound law that changes "è" to "ò" after an accented syllable, i.e. PIE|kʷetwóres < PIE|kʷétwores < PIE|kʷétweres.

Rix invokes the rule in the 1998 preface to the "Lexikon der indogermanischen Verben" (p. 22) to explain why in the PIE Perfect the root "ó" grade is accented, e.g. PIE|ǵe-ǵónh- / ǵé-ǵn̥h- < PIE|ǵé-ǵenh- / ǵé-ǵn̥h- "created/engendered".

The rule has been invoked by Mottausch to explain accented "ó" grades in PIE nominal ablaut.

References

*G. Klingenschmitt "Die Lateinische Nominalflexion" (1992), p. 44.
*M. Kümmel, "Stativ und Passivaorist" (1996), p. 9.
*K.-H. Mottausch, "Die idg. Nominalflexion und die o-Stufe" HS 113 (2000).
*K.-H. Mottausch, "Die thematischen Nomina im Idg." HS 114 (2001).
*H. Rix, "sūdor and sīdus" in: FS Knobloch (ed. Ölberg, 1985), p. 348
*K. Stüber, "Die primären s-Stämme" (2002), p. 24f.