Old Low Franconian or Old Dutch is regarded as the primary stage in the development of a separate Dutch language. The "Low" in Old Low Franconian refers to the Frankish spoken in the Low Countries where it was not influenced by the High German consonant shift, as opposed to Central and high Franconian in Germany. The latter would as a consequence evolve with Allemanic into Old High German. At more or less the same time the Ingvaeonic nasal spirant law led to the development of Old Saxon, Old Frisian (Anglo-Frisian) and Old English (Anglo-Saxon). Hardly influenced by either development, Old Dutch remained close to the original language of the Franks, the people that would rule Europe for centuries. The language however, did experienced developments on its own, like final-obstruent devoicing in a very early stage. In fact, by judging from the find at Bergakker, it would seem that the language already experienced this characteristic during the Old Frankish period.
Why isn't Old Dutch the Original language of the Franks?
experienced developments on its own