Verner's law

Verner's law explains the voicing of certain Proto-Germanic fricatives when the preceding syllable was unstressed in Proto-Indo-European. It accounts for alternations that Grimm's law alone could not explain.

Proto-Indo-European accent: The system of stress and pitch prominence reconstructed for Proto-Indo-European words. Whether the syllable before a consonant was stressed determined whether Verner's law voiced it.
Proto-Germanic *faþēr: The reconstructed Proto-Germanic word ancestral to English father and related Germanic forms. Its voiced medial fricative reflects Verner's law after an unstressed preceding syllable.
Karl Verner: A Danish linguist who formulated Verner's law in 1875. He identified the role of earlier stress in explaining Germanic consonant exceptions.
Indo-European accent: The reconstructed stress and pitch systems of Proto-Indo-European and its descendant languages. Verner's law made ancestral accent essential to explaining Germanic consonant correspondences.
Grimm's law: A set of regular sound changes that transformed Proto-Indo-European stops into Proto-Germanic consonants. Verner's law explains why Grimm's law's voiceless fricatives sometimes became voiced.
Proto-Germanic *broþēr: The reconstructed Proto-Germanic word ancestral to English brother and related Germanic forms. Its voiced fricative contrasts with the voiceless consonant expected from Grimm's law alone.
August Schleicher: A German linguist known for influential work on Indo-European comparative linguistics and reconstruction. Verner's 1875 paper addressed a problem in the comparative framework Schleicher helped develop.
Grammatical alternation: A regular difference in form among related words or grammatical forms. Vernerian voicing could create consonant alternations within paradigms as stress shifted.
Proto-Germanic: The reconstructed ancestor of the Germanic languages, spoken before their earliest written records. Verner's law describes a sound change during the development of this ancestral language.
Proto-Germanic *maizō: A reconstructed Proto-Germanic comparative meaning 'more,' ancestral to forms such as English more. The medial voiced sibilant illustrates the law's effect after an originally unstressed syllable.

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