A first LVCSR system for Luxembourgish, a low-resourced European language Martine Adda-Decker 1,2 , Lori Lamel 2 , Gilles Adda 2 , and Thomas Lavergne 3 1 Laboratory of Phonetics and Phonology, CNRS-Paris 3/Sorbonne Nouvelle, France 2 Spoken Language Processing Group LIMSI-CNRS, Orsay, France 3 ILES Group LIMSI-CNRS, Orsay, France martine.adda-decker@univ-paris3.fr, (lori.lamel,gilles.adda,thomas.lavergne)@limsi.fr Abstract. Luxembourgish is embedded in a multilingual context on the divide between Romance and Germanic cultures and remains one of Europe’s low-resourced languages. We describe our efforts in building a large vocabulary ASR system for such a “minority” language without resorting to any prior transcribed audio training data. Instead, acous- tic models are derived from major European languages. Furthermore, most Luxembourgish written sources include significant parts in other languages. This poses specific challenges to Language Model estimation. Some scientific and technological issues addressed include: (i) how to build acoustic models if no labeled acoustic training data are available for the under-resourced target language? (ii) how to make use of the new system to accelerate resource production for the target language? (iii) how to build a vocabulary and a language model with multilingual written texts? (iv) how to determine the “best” phonemic inventory for ASR? First ASR results illustrate the accuracy of the various sets of monolingual and multilingual acoustic models and what these suggest concerning language typology issues. Keywords: Forced alignment; acoustic modeling; multilingual models; Luxembourgish; Germanic languages, Romance languages. 1 Introduction Luxembourg, a small country of less than 500,000 inhabitants in the center of Western Europe, is composed of about 65% of native inhabitants and 35% of im- migrants. The national language, Luxembourgish ("Lëtzebuergesch"), has only been considered as an official language since 1984 and is spoken by natives [1]. The population (both natives or residents) generally speak one of Luxembourg’s other official languages: French or German. Recently, English has joined the set of languages of communication, mainly in professional environments. As pointed out by [2] and [3], Luxembourgish should be considered as a partially under-resourced language, due to the fact that the written production remains relatively low, and linguistic knowledge and resources, such as lexica and