Within the Indo-European language tree, Dutch is grouped within the Germanic languages, which means it shares a common ancestor with languages such as English, German, and Scandinavian languages. All Germanic languages are united by subjection to the sound shifts of Grimm's law and <answer>Verner's law</answer> which originated in the Proto-Germanic language and define the basic differentiating features from other Indo-European languages. This assumed to have originated in approximately the mid-first millennium BCE in Iron Age northern Europe.
Along with Grimm's law, what's the other rule for Germanic-sounding speech called?
Verner's law