古ザクセン語
Old English, Old Frisian and (to a lesser degree) Old Saxon share the application of the Ingvaeonic nasal spirant law. Old Dutch was considerably less affected than the other three languages, but a dialect continuum formed or existed between both Old Dutch and Old Saxon, as well as Old Dutch and Old Frisian. Despite sharing some particular features, a number of disparities separate Old Saxon, Old English, and Old Dutch. One such difference is that Old Dutch uses "-a" as its plural a-stem noun ending, while Old Saxon and Old English employs "-as" or "-os". Much of the grammatical variation between Old Dutch and Old Saxon is similar to that between Old Dutch and Old High German.