PASCAL - Pattern Analysis, Statistical Modelling and Computational Learning

Analysis of Morph-Based Speech Recognition and the Modeling of Out-of-Vocabulary Words Across Languages
Mathias Creutz, Teemu Hirsimäki, Mikko Kurimo, Antti Puurula, Janne Pylkkönen, Vesa Siivola, Matti Varjokallio, Ebru Arisoy, Murat Saraclar and Andreas Stolcke
In: Human Language Technologies / The Annual Conference of the North American Chapter of the Association for Computational Linguistics (NAACL-HLT 2007), 23-25 Apr 2007, Rochester, NY, USA.


We analyze subword-based language models (LMs) in large-vocabulary continuous speech recognition across four "morphologically rich'' languages: Finnish, Estonian, Turkish, and Egyptian Colloquial Arabic. By estimating n-gram LMs over sequences of morphs instead of words, better vocabulary coverage and reduced data sparsity is obtained. Standard word LMs suffer from high out-of-vocabulary (OOV) rates, whereas the morph LMs can recognize previously unseen word forms by concatenating morphs. We show that the morph LMs generally outperform the word LMs and that they perform fairly well on OOVs without compromising the accuracy obtained for in-vocabulary words.

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EPrint Type:Conference or Workshop Item (Paper)
Project Keyword:Project Keyword UNSPECIFIED
Subjects:Natural Language Processing
ID Code:3507
Deposited By:Mathias Creutz
Deposited On:11 February 2008