This thesis is part of a descriptive work in acoustic phonetics, with the aim of studying the productions of Luxembourgish vowels in native and non-native speech. Its objective is to conciliate the variation of Luxembourgish, mainly a spoken language, composed of many regional varieties, evolving in a multilingual context, and the learning of Luxembourgish as a foreign language in the Grand-Duchy of Luxembourg. As we assume the fact that language learning implies knowledge of sound contrast in speech, we investigate the productions of speakers whose mother tongues have different features than Luxembourgish, such as French, to see whether if the contrast are reproduced in non-native speech. Productions of French speakers are compared to those of native speakers from the region around the capital city of the Grand-Duchy of Luxembourg, whose variety serves as a reference to the teaching of Luxembourgish as a foreign language. The purpose of the study is the following :- to extend the descriptions on the acoustic properties of vowels produced in a regional variety of the Grand-Duchy of Luxembourg,- to highlight the specific difficulties of productions by French learners of Luxembourgish,- to interpret the results regarding the teaching of Luxembourgish as a foreign language.Fieldwork and the creation of a corpus through recordings of 10 Luxembourg speakers and 10 French speakers are an important part of the empirical work. We obtained a corpus of 12 hours and a half of spoken and spontaneous speech, including native speech and not native of Luxembourgish and also native speech of French. This corpus represents a first corpus containing native and non-native speech of Luxembourgish and enables to conduct different comparative studies. In our thesis, we did comparative analyses of the data in read speech. The methodology we used made it possible to compare data of native and non-native speech and also data of the L1 and L2 of French speakers.The results gave information about native and non-native productions of ...