Development of the Arabic Loria Automatic Speech Recognition system (ALASR) and its evaluation for Algerian dialect

International audienceThis paper addresses the development of an Automatic Speech Recognition system for Modern Standard Arabic (MSA) and its extension to Algerian dialect. Algerian dialect is very different from Arabic dialects of the Middle-East, since it is highly influenced by the French language. In this article, we start by presenting the new automatic speech recognition named ALASR (Arabic Loria Automatic Speech Recognition) system. The acoustic model of ALASR is based on a DNN approach and the language model is a classical n-gram. Several options are investigated in this paper to find the best combination of models and parameters. ALASR achieves good results for MSA in terms of WER (14.02%), but it completely collapses on an Algerian dialect data set of 70 minutes (a WER of 89%). In order to take into account the impact of the French language, on the Algerian dialect, we combine in ALASR two acoustic models, the original one (MSA) and a French one trained on ESTER corpus. This solution has been adopted because no transcribed speech data for Algerian dialect are available. This combination leads to a substantial absolute reduction of the word error of 24%. c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 3rd International Conference on Arabic Computational Linguistics

Investigating the Use of Morphological Decomposition and Diacritization for Improving Arabic LVCSR

One of the challenges related to large vocabulary Arabic speech recognition is the rich morphology nature of Arabic language which leads to both high out-of-vocabulary (OOV) rates and high language model (LM) perplexities. Another challenge is the absence of the short vowels (diacritics) from the Arabic written transcripts which causes a large difference between spoken and written language and thus a weaker connection between the acoustic and language models. In this work, we try to address these two important challenges by introducing both morphological decomposition and diacritization in Arabic language modeling. Finally, we are able to obtain about 3.7 % relative reduction in word error rate (WER) with respect to a comparable non-diacritized full-words system running on our test set. Index Terms: speech recognition, morphological decomposition, diacritization, Arabi