# Grimm's Law **Domain:** Linguistics / Historical Phonology **Doc Type:** Concept Node **Maturity:** Developed ## Definition **Grimm's Law** describes a regular set of consonant shifts that separated the Germanic languages, including English, from the rest of the Indo-European family. Comparing Latin and English shows the pattern: *pater / father* (p → f), *tres / three* (t → th), *centum / hundred* (k → h), *decem / ten* (d → t), and *genu / knee* (g → k). The Danish scholar Rasmus Rask described the correspondences in 1818, and Jacob Grimm set them out systematically in 1822. The law turned etymology from guesswork into a discipline with testable rules. ## Corpus Context Grimm's Law supplies the consonant side of phonetic hunting: knowing which sounds trade places lets a word's distant relatives come into view. See [[wiki/Phonetic Etymology|Phonetic Etymology]]. ## Relationships - **Process family:** [[wiki/Sound Change|Sound Change]]. - **Ancestor:** [[wiki/Proto-Indo-European|Proto-Indo-European]]. - **Practice:** [[wiki/Phonetic Etymology|Phonetic Etymology]]. - **Corpus project:** [[projects/Ten Years Building a Symbolic Language Engine|Ten Years Building a Symbolic Language Engine]], Bryant McGill's symbolic language engine, built from 1994 into the mid-2000s, with its phonological engine, sound indexes, and lexical knowledge graph. ## Sources - Jacob Grimm, *Deutsche Grammatik*, 2nd ed., vol. 1 (1822). - Rasmus Rask, *Undersøgelse om det gamle Nordiske eller Islandske Sprogs Oprindelse* (1818). ## See Also [[wiki/Ablaut|Ablaut]] · [[wiki/Etymology|Etymology]]