Weise's law

In historical linguistics, Weise's law describes the loss of palatal quality that some consonants undergo in specific contexts in the Proto-Indo-European language.

[3] These sounds are articulated both with the back part of the tongue and the hard palate of the mouth, represented with *ḱ, *ǵ, and *ǵʰ, where the asterisk signifies a reconstructed or unattested form.

[4] Both of these sets were further contrasted with the labiovelar consonants, likely pronounced with a simultaneous articulation with the back part of the tongue against the soft palate and the rounding of the lips, represented by *kʷ, *gʷ, and *gʷʰ.

[13][14] Oskar Weise first described a problem in correspondences between Ancient Greek and Sanskrit cognates in his 1881 article "Is initial γ dropped before λ?"

[16] According to Alwin Kloekhorst in 2011, Weise's original article has "been largely forgotten by the scholarly world", but its findings have appeared sporadically in linguistic literature with some of it needing revision in light of other research.

[22] The 2011 defense conglomerates several different sources on the topic, some referencing Weise and some not, and summarizes its general characteristics, its relative chronology, and possible violations.

[27] Sanskrit contains many apparent violations of the rule, particularly where the surface representation of the word contains śr- or hr-, implying a derivation from an unmodified *ḱr- or *ǵʰr- source.

[31] Other apparent violations occur in contexts in which the palatovelar consonant and *r cross a morphemic boundary, such as between an affix and the root it modifies, or share a clear derivational relationship with another word that would not have been subjected to the sound law, leading to an analogical change.

[32] With respect to the first apparent violation, the Sanskrit word अज्र ájra 'field, plain' is derived from *h₂éǵ-ro- 'field, pasturage', where the expected outcome is *अग्र *ágra.

Kloekhorst suggests that the high front vowel *i may have palatalized the preceding *r, giving no motivation to depalatalize the initial palatovelar sound.

[38] Kloekhorst argues that it probably occurred much earlier, after the divergence of the Anatolian languages (c. 4500 BC),[39] since the distribution of late Proto-Indo-European *u and *r underwent an exchange in placement, or metathesis, which only occurred after both the Anatolian language family had diverged from Proto-Indo-European and palatovelars had undergone the depalatalization described by Weise's law.

This explains exceptions such as Sanskrit श्मश्रु śmáśru 'beard', which derives from the form *smóḱ-ru- rather than from the earlier *smóḱ-ur, attested in Hittite 𒍝𒈠𒀭𒆳 zama(n)kur 'beard'.