Outside of the brief time window of 1806 and 1813, East Frisia outside of the Dutch state though its western counterpart was one of the Seven Provinces. East Frisia had otherwise been independent until its annexation by Prussia in 1654 (a peaceful one as the Prussians respected Frisian autonomy), though under Dutch influence. What if East Frisia had become part of the Netherlands instead? No set PoD for this one. What would it mean for the Frisian language/people?