Grimm's Law: Germanic Consonant Shift

Glossary of Grammatical and Rhetorical Terms

Jacob Grimm
Grimm's law was outlined by German philologist Jacob Grimm.

 Imagno / Getty Images

Grimm's Law defines the relationship between certain stop consonants in Germanic languages and their originals in Indo-European [IE]; these consonants underwent shifts that changed the way they are pronounced. This law is also known as the Germanic Consonant Shift, First Consonant Shift, First Germanic Sound Shift, and Rask's Rule.

The basic principle of Grimm's law was discovered in the early 19th century by Danish scholar Rasmus Rask. Soon after, it was outlined in detail by German philologist Jacob Grimm. What was once a probing theory is now a well-established law in the field of linguistics.

What Is Grimm's Law?

Grimm's law is a set of rules dictating how a handful of Germanic letters differ from their Indo-European cognates. Roshan and Tom Mcarthur summarize the rules within this law as follows: "Grimm's Law holds that unvoiced IE stops became Germanic unvoiced continuants, that voiced IE stops became Germanic unvoiced stops, and that unvoiced IE continuants became Germanic voiced stops," (Mcarthur and Mcarthur 2005).

Studying Grimm's Law

A detailed outline—as thorough as it was—did little to explain the "why" behind this law. Because of this, modern researchers still rigorously study the phenomenon presented by Grimm's Law in search of clues that will make its origins more clear. They look for the patterns in history that launched these language changes.

One of these linguists, researcher Celia Millward, writes: "Beginning sometime in the first millennium B.C. and perhaps continuing over several centuries, all the Indo-European stops underwent a complete transformation in Germanic," (Millward 2011). 

Examples and Observations

For more findings regarding this rich branch of linguistics, read these observations from experts and scholars.

Sound Changes

"Rask's and Grimm's work ... succeeded in establishing once and for all that the Germanic languages are indeed part of Indo-European. Secondly, it did so by providing a brilliant account of the differences between Germanic and the classical languages in terms of a set of amazingly systematic sound changes," (Hock and Joseph 1996).

A Chain Reaction

"Grimm's Law can be considered a chain reaction: aspirated voice stops become regular voiced stops, voiced stops, in turn, become voiceless stops, and voiceless stops become fricatives ... Examples of this change taking place at the beginning of words are provided [below]. ... Sanskrit is the first form given (except for kanah which is Old Persian), Latin the second, and English the third.

It is important to remember that the change takes place only once in a word: dhwer corresponds to door but the latter does not change to toor: Thus, Grimm's Law distinguishes Germanic languages from languages such as Latin and Greek and modern Romance languages such as French and Spanish. ... The change probably took place a little over 2,000 years ago," (van Gelderen 2006).

F and V

"Grimm's Law ... explains why Germanic languages have 'f' where other Indo-European languages have 'p.' Compare English father, German vater (where 'v' is pronounced 'f'), Norwegian far, with Latin pater, French père, Italian padre, Sanskrit pita," (Horobin 2016).

A Sequence of Changes

"It remains unclear whether Grimm's Law was in any sense a unitary natural sound change or a series of changes that need not have occurred together. It is true that no sound change can be shown to have occurred between any of the components of Grimm's Law, but since Grimm's Law was among the earliest Germanic sound changes, and since the other early changes that involved single non-laryngeal obstruents affected only the place of articulation and rounding of dorsals ... that could be an accident. In any case, Grimm's Law is most naturally presented as a sequence of changes that counterfed each other,"​ (Ringe 2006).


  • Hock, Hans Henrich, and Brian D. Joseph. Language History, Language Change, and Language Relationship. Walter de Gruyter, 1996.
  • Horobin, Simon. How English Became English. Oxford University Press, 2016.
  • McArthur, Tom, and Roshan Mcarthur. Concise Oxford Companion to the English Language. Oxford University Press, 2005.
  • Millward, Celia M. A Biography of the English Language. 3rd ed. Cengage Learning, 2011.
  • Ringe, Donald. A Linguistic History of English: From Proto-Indo-European to Proto-Germanic. Oxford University Press, 2006.
  • Van Gelderen, Elly. A History of the English Language. John Benjamins, 2006.
mla apa chicago
Your Citation
Nordquist, Richard. "Grimm's Law: Germanic Consonant Shift." ThoughtCo, Aug. 27, 2020, Nordquist, Richard. (2020, August 27). Grimm's Law: Germanic Consonant Shift. Retrieved from Nordquist, Richard. "Grimm's Law: Germanic Consonant Shift." ThoughtCo. (accessed March 24, 2023).