Grassmann's law

Grassmann's law is a dissimilation rule in ancient Greek and Sanskrit that removes aspiration from one of two aspirated stops in a word.

Aspiration (phonetics): Aspiration is a burst of breath accompanying the release of a consonant. The rule changes whether a stop is aspirated.
Ancient Greek: Ancient Greek is the language spoken and written in Greece from the earliest Greek records through late antiquity. Grassmann’s law is visible in Greek verb and noun forms.
Hermann Grassmann: Hermann Grassmann was a German mathematician and linguist who formulated the dissimilation law bearing his name. His 1863 study established the rule as a comparative linguistic principle.
Bartholomae's law: Bartholomae's law is a Proto-Indo-Iranian sound change affecting clusters of voiced aspirated stops and voiceless obstruents. It changes voicing and aspiration in clusters rather than dissimilating two aspirated stops.
Dissimilation: Dissimilation is a sound change that makes similar sounds in a word less alike. Grassmann’s law is a specific dissimilation of aspiration.
Sanskrit: Sanskrit is an ancient Indo-Aryan language preserved in religious, literary, and scholarly texts. Sanskrit displays the law independently in inherited and inflected forms.
Franz Bopp: Franz Bopp was a German linguist who helped establish comparative study of Indo-European languages. His comparative grammar discussed the Greek and Sanskrit aspiration pattern before Grassmann’s formulation.
Sievers' law: Sievers' law describes alternation between consonantal and syllabic forms of Indo-European sonorants after syllable-weight conditions. It is a prosodically conditioned alternation, not loss of repeated aspiration.
Aspirated consonant: An aspirated consonant is produced with an audible burst of breath after its release. Two such stops in one word trigger the rule.
Greek perfect tense: The Greek perfect is a verbal category that presents a state resulting from a prior event. Perfect forms often show aspiration loss in the reduplicated syllable.

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