As a young and comparatively little-standardised Germanic language, Luxembourgish is characterised by a very high degree of variation, which in many cases is still unexplored. This also applies to the morphological varia- tion of the superlative (dat schéinst / dat schéinst-en / dat schéinst-en-t Päerd ‘the most beautiful horse’) and the adjectival participle (e gefëllt-en / e gefëllt- en-e Croissant ‘a filled croissant’). This empirical study is the first attempt to fill this research gap. On the one hand, the chapter aims to explore the variation of these phenomena from a more classical perspective, that is, by analysing inter- individual variation (IEV); the purpose of it is to identify possible linguistic and social constraints that influence the variation. On the other hand, the chapter also focuses on intra-individual variation (IAV), i.e. variation within a speaker that is situationally independent. This analysis aims to evaluate the results of the IEV perspective and also to reveal further specificities of the variation. Studying a large corpus of crowd-sourced speech data leads to several findings. It becomes apparent, for example, that part of the morphological variation can be explained by the influence and interaction of different linguistic factors. Furthermore, there is evidence that IAV manifests in various forms: as the expression of individual linguistic preferences, as the expression of linguistic insecurities and as the expression of language change.