格林定律
Having Verner's law act before Grimm's law may help explain the little evidence that there is for the earliest Germanic phonology. There is some evidence for dating Grimm's law changes only to the end of the first century BCE. In particular, the tribal name recorded as Cimbri by the Romans and the river-name recorded as "Vaculus" (now known as the Waal) suggest that the change from "k" to "h" had still not happened around the first century BCE, when Romans were rendering those words into Latin (unless they were rendering the early Germanic () sound as a because their own did not often occur between vowels and was at any rate already in the process of going silent). If Grimm's law "was" operative only in the first century BCE and Verner's law applied after it (followed in turn by the shift of stress to initial syllables), then three dramatic changes would have had to happen in quick succession. Such a rapid set of language changes seems implausible to some scholars.