Grimm's Law
Branch: GermanicDiscovered by Jacob Grimm (1822)
PIE *p, *t, *k → PGmc *f, *þ, *h; PIE *b, *d, *g → PGmc *p, *t, *k; PIE *bʰ, *dʰ, *gʰ → PGmc *b, *d, *gA set of consonant shifts that differentiate the Germanic languages from other IE branches. PIE voiceless stops became voiceless fricatives, voiced stops became voiceless stops, and voiced aspirated stops became voiced stops (or fricatives). This is the defining innovation of the Germanic branch.
Sound Correspondences
| PIE Form | Reflex | Environment | Examples |
|---|---|---|---|
*p | PGmc *f | General | *ph₂tḗr → *fadēr (father); *ped- → *fōts (foot) |
*t | PGmc *þ | General | *tréyes → *þrīz (three); *tu → *þū (thou) |
*k | PGmc *h | General | *ḱerd- → *hertō (heart); *ḱm̥tóm → *hundą (hundred) |
*kʷ | PGmc *hw | General | *kʷód → *hwat (what); *kʷis → *hwiz (who) |
*b | PGmc *p | General | *dʰewb- → *deupą (deep) |
*d | PGmc *t | General | *déḱm̥ → *tehun (ten); *h₁ed- → *etaną (eat) |
*g | PGmc *k | General | *ǵénu → *knewą (knee); *h₂eǵ- → *aką (ache) |
*gʷ | PGmc *kw | General | *gʷṓws → *kōz (cow); *gʷem- → *kwemaną (come) |
*bʰ | PGmc *b/β | General | *bʰer- → *beraną (bear); *bʰréh₂tēr → *brōþēr (brother) |
*dʰ | PGmc *d/ð | General | *dʰeh₁- → *dōną (do); *dʰwer- → *durz (door) |
*gʰ | PGmc *g/ɣ | General | *gʰostis → *gastiz (guest); *gʰans- → *gans (goose) |
Discussion
Grimm's Law, formulated by Jacob Grimm in 1822 in his Deutsche Grammatik, describes the systematic sound changes that differentiate the Germanic languages from other Indo-European branches. It is one of the foundational discoveries of historical linguistics and served as powerful evidence for the regularity of sound change.
The law describes three parallel shifts affecting the Indo-European stop consonants. First, the PIE voiceless stops *p, *t, *k became voiceless fricatives *f, *þ (th), *h in Proto-Germanic. This is visible in pairs like Latin pater versus English father, Latin tres versus English three, and Latin centum versus English hundred (where the initial *k became h).
Second, the PIE voiced stops *b, *d, *g became voiceless stops *p, *t, *k in Proto-Germanic. Examples include Latin decem versus English ten, Latin genus versus English kin, and Latin labium versus English lip.
Third, the PIE voiced aspirated stops *bʰ, *dʰ, *gʰ became voiced stops (later fricatives in some positions) *b, *d, *g in Proto-Germanic. This is seen in Sanskrit bharati versus English bear, Sanskrit dha- versus English do, and Latin hostis (from *gʰostis) versus English guest.
These three shifts operate as a chain, often called the Germanic consonant shift or erste Lautverschiebung. They apply systematically across the vocabulary, with exceptions explained by Verner's Law and other conditioning factors. Grimm's Law was instrumental in establishing the Neogrammarian principle that sound laws operate without exceptions, a cornerstone of modern historical linguistics.