Grimm’s law

In HISTORICAL LINGUISTICS and PHILOLOGY, a SOUND LAW first worked out in 1822 by Jakob Grimm (1785–1863) which shows the regular way in which the Germanic SOUND SYSTEM diverged from that of Indo-European. Nine sets of CORRESPONDENCES were shown, which fell into a clear PHONETIC pattern. VOICED ASPIRATES (a term which includes both aspirated PLOSIVES and FRICATIVES) in Indo-European became voiced plosives in Germanic; voiced plosives became voiceless plosives; and voiceless plosives became voiceless aspirates. These relationships explain, for example, why words which begin with /p/ in Latin, Greek or Sanskrit generally have /f/ in English (e.g. pater – father). Certain exceptions to this law were explained by later philologists.