Germanic languages
Linguistic developments

The subgroupings of the Germanic languages are defined by shared innovations. It is important to distinguish innovations from cases of linguistic conservatism. That is, if two languages in a family share a characteristic that is not observed in a third language, that is evidence of common ancestry of the two languages only if the characteristic is an innovation compared to the family's proto-language.

The following innovations are common to the Northwest Germanic languages (all but Gothic):

The following innovations are also common to the Northwest Germanic languages but represent areal changes:

The following innovations are common to the West Germanic languages:

The following innovations are common to the Ingvaeonic subgroup of the West Germanic languages, which includes English, Frisian, and in a few cases Dutch and Low German, but not High German:

The following innovations are common to the Anglo-Frisian subgroup of the Ingvaeonic languages:
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