peer reviewed ; Like many other small languages in Europe, Luxembourgish is embedded in a specific multilingual situation, which is leading to intricate patterns of language variation. While language contact - here: with German and French - is clearly one of the main factors in language variation, Luxembourgish is furthermore characterized by regional variation within the country and internal changes, both related to the mainly spoken status of Luxembourgish and ongoing language standardization. In order to address language variation from a broad perspective, in this article a crowd-sourcing approach for data collection and several case studies for linguistic variables are going to be presented. For data collection a novel smartphone application has been developed which allows to elicit variable linguistic phenomena in a coherent way and which is at the same time easy to use for the participants. This technique allowed to collect audio speech data for over 3700 speakers, which permits to analyze variation on the phonetic, morphological, syntactic and lexical level on a hitherto unachieved quantitative level. The aims of this long-term project are thus to document spoken Luxembourgish and its variation and to develop a new kind of linguistic atlas, in which variation is not only illustrated as a geographical phenomenon but further correlated with several social and demographic factors. Data analyses will then provide a comprehensive picture of language variation and general trends in Luxembourgish.