Grimm's law

Grimm's Law (also known as the First Germanic Sound Shift or Rask's rule) is a set of statements named after Jacob Grimm describing the inherited Proto-Indo-European (PIE) stop consonants as they developed in Proto-Germanic (the common ancestor of the Germanic branch of the Indo-European family) in the 1st millennium BC. It establishes a set of regular correspondences between early Germanic stops and fricatives and the stop consonants of certain other centum Indo-European languages (Grimm used mostly Latin and Greek for illustration).

History

Grimm's law describes the first non-trivial systematic sound change to be discovered in philology; its formulation was a turning point in the development of linguistics, enabling the introduction of a rigorous methodology to historical linguistic research. The correspondence between Latin p and Germanic f was first noted by Friedrich von Schlegel in 1806. In 1818, Rasmus Christian Rask elaborated the set of correspondences to include other Indo-European languages, such as Sanskrit and Greek, and the full range of consonants involved. In 1822, Jacob Grimm formulated the law as a general rule in his book Deutsche Grammatik, and extended it to include standard German. (Jacob was the elder of the Brothers Grimm.)