Lautverschiebung \Laut"ver*schie`bung\
   (lout"f[e^]r*sh[=e]`b[oo^]ng), n.; pl. Lautverschiebungen
   (lout"f[e^]r*sh[=e]`b[oo^]ng*en). [G.; laut sound +
   verschiebung shifting.] (Philol.)
   (a) The regular changes which the primitive Indo-European
       stops, or mute consonants, underwent in the Teutonic
       languages, probably as early as the 3d century b. c.,
       often called the first Lautverschiebung, sound
       shifting, or consonant shifting.
   (b) A somewhat similar set of changes taking place in the
       High German dialects (less fully in modern literary
       German) from the 6th to the 8th century, known as the
       second Lautverschiebung, the results of which form the
       striking differences between High German and The Low
       German Languages. The statement of these changes is
       commonly regarded as forming part of Grimm's law,
       because included in it as originally framed.
       [Webster 1913 Suppl.]