These were in the Dutch language area calqued as the exonyms Nederduits and Hoogduits and referred now to the Germanic spoken in the German state.
As a result, the Hoog ("High") was dropped in the Dutch exonym Hoogduits in the sense of the German standard language, meaning that Duits narrowed down as Dutch exonym for German.
All Germanic languages are subject to the Grimm's law and Verner's law sound shifts, which originated in the Proto-Germanic language and define the basic features differentiating them from other Indo-European languages.
This is assumed to have taken place in approximately the mid-first millennium BCE in the pre-Roman Northern European Iron Age.
Moreover, Nederduits lost its meaning as endonym for Dutch, and Nederlands prevailed as sole Dutch endonym.
Old Dutch branched off more or less around the same time as Old English (Anglo-Saxon), Old High German, Old Frisian and Old Saxon did.
On the other hand, Dutch has been replaced in adjacent lands in nowadays France and Germany.
Although in Britain the name Englisc replaced theodisce on an early age, speakers of West Germanic in other parts of Europe kept on using it as a reference to their local speech.
The early form of Dutch was a set of Franconian dialects spoken by the Salian Franks in the fifth century, and thus, it has developed through Middle Dutch to Modern Dutch over the course of 15 centuries.
During that period, it forced Old Frisian back from the western coast to the north of the Low Countries, and influenced or even replaced Old Saxon spoken in the east (contiguous with the Low German area).
the Germanic dialects spoken on higher grounds) for the German standard language came into use.
However, the 19th century saw the rise of dialectology and the categorisation of dialects.