He used it analogously to High German (Hochdeutsch), pointing out that Ivar Aasen, the creator of Nynorsk orthography, had especially valued the dialects of the mountainous areas of middle and western Norway, as opposed to the dialects of the lowlands of eastern Norway, which Hannaas called flatnorsk (Flat Norwegian, like Plattdeutsch).
Empregouno analogamente ao termo Alto alemán (Hockdeutsch), salientando o feito de que Ivar Aasen, creador da ortografía Nynorsk, dese unha importancia especial aos dialectos das áreas montañosas do centro e oeste de Noruega, e non aos dialectos das zonas baixas do leste de Noruega, ás que Hanaas chamou flatnorsk (Noruega plana, análogo a Plattdeutsch).