Multilinguality in speech and spoken language systems

Abstract

Building modern speech and language systems currently requires large data resources such as texts, voice recordings, pronunciation lexicons, morphological decomposition information and parsing grammars. Based on a study of the most important differences between language groups, we introduce approaches to efficiently deal with the enormous task of covering even a small percentage of the world's languages. For speech recognition, we have reduced the resource requirements by applying acoustic model combination, bootstrapping and adaption techniques. Similar algorithms have been applied to improve the recognition of foreign accents. Segmenting language into appropriate units reduces the amount of data required to robustly estimate statistical models. The underlying morphological principles are also used to automatically adapt the coverage of our speech recognition dictionaries with the Hypothesis-Driven Lexical Adaptation (HDLA) algorithm. This reduces the out-of-vocabulary problems encountered in agglutinative languages. Speech recognition results are reported for the read GlobalPhone database and some broadcast news data. For speech translation, using a task-oriented Interlingua allows to build a system with N languages with linear, rather than quadratic effort. We have introduced a modular grammar design to maximize reusability and portability. End-to-end translation results are reported on a travel-domain task in the framework of C-STAR.