Boukólos rule

The boukólos rule is a phonological rule of the Proto-Indo-European language (PIE). It states that a labiovelar stop (*kʷ, *gʷ, *gʷʰ) dissimilates to an ordinary velar stop (*k, *g, *gʰ) next to the vowel *u or its corresponding glide *w.

The rule is named after an example, the Ancient Greek word βουκόλος (bou-kólos; from Mycenaean Greek qo-u-ko-ro /gʷou̯kolos/^[1]) "cowherd", ultimately from PIE *gʷou-kolos, dissimilated from *gʷou-kʷolos. If the labiovelar had not undergone dissimilation, the word should have turned out as *bou-pólos, as in the analogously constructed αἰπόλος (ai-pólos) "goatherd" < *ai(ǵ)-kʷolos.^[2] The same dissimilated form *gʷou-kolos is the ancestor of Proto-Celtic *bou-koli-, the source of Welsh bugail (which would have had -b- rather than -g- if it had come from a form with *-kʷ-) and Irish buachaill, which is the common word for "boy" in the modern language.^[3]

Another example could be the Greek negation οὐκ[ί] (ouk[í]), which Warren Cowgill has interpreted as coming from pre-Greek *ojukid < *(ne) h₂oju kʷid, meaning approximately "not on your life". Without the boukólos rule, the result would have been *οὐτ[ί] (out[í]).^[4]

The rule is also found in Germanic, mainly in verbs, where labiovelars are delabialised by the epenthetic -u- inserted before syllabic resonants:^[5]

• Old High German queman ("to come"), past participle cuman ("come"), from Proto-Germanic *kwemaną and *kumanaz
• Gothic saiƕan, Old High German sehan ("to see"), past plural OHG sāgun ("saw"), from Proto-Germanic *sehwaną and *sēgun (-g- results from earlier -k- through Verner's law)

See also

• Weise's law, a similar Proto-Indo-European sound law affecting the palatovelar consonants

References

1. Beekes, Robert Stephen Paul (2011). Comparative Indo-European Linguistics: An Introduction. John Benjamins Publishing. ISBN 978-90-272-1185-9. Retrieved 12 August 2017.
2. Fortson, Benjamin W. IV (2004). Indo-European Language and Culture. Blackwell Publishing. p. 64. ISBN 1-4051-0316-7.
3. Matasović, Ranko (2009). Etymological Dictionary of Proto-Celtic. Leiden: Brill. p. 72. ISBN 978-90-04-17336-1.
4. Fortson (2004:133)
5. Ringe, Donald A. (2017). From Proto-Indo-European to Proto-Germanic. Linguistic history of English, v. 1 (2nd ed.). Oxford: Oxford University Press. pp. 111–112. ISBN 978-0-19-955229-0.