Verner's law /ˈvɜːnəz/

• 1. 

  N a modification of Grimm's Law accommodating some of its exceptions. It states that noninitial voiceless fricatives in Proto-Germanic occurring as a result of Grimm's law became voiced fricatives if the previous syllable had been unstressed in Proto-Indo-European 威尔纳音变法则 [linguistics]