More generally called n-deletion or n-apocope, it appears to varying extents in all dialects of the Western group of High German, including West Central German (notably Luxembourgish, Colognian and Hessian), High Franconian and Alemannic; and excludes all dialects of the Eastern group, such as Austro-Bavarian and the colonial dialects east of the Elbe-Saale line (including Standard German and Yiddish).
[2] The Eifel rule is pervasive in Luxembourgish as -n is a common ending for verbs, plural nouns, inflected adjectives and function words.
At the same time, certain content words do undergo n-deletion, e.g. Wäi(n) (wine), Stee(n) (stone), geschwë(nn) (soon).
This is due in part to slight morphological differences between the Moselle Franconian languages of the upper Eifel regions (High Eifel and Schneifel), and the Ripuarian languages of the North- and Vordereifel region and the Cologne Lowland, to which Colognian belongs.
For example, with the words bovve (up, up there) and en (in, into), one may build the phrase: bovve en der Schaaf (up there into the cupboard) which depending on stress and voice flow inside a complete sentence is spoken as either [ˈbɔvə ʔen dɐ ˈʃaˑf] or [ˈbɔvən‿en dɐ ˈʃaˑf].