Multilingual speech recognition in seven languages

In this study we present approaches to multilingual speech recognition. We first define different approaches, namely portation, cross-lingual and simultaneous multilingual speech recognition. We will show some experiments performed in the fields of multilingual speech recognition. In recent years we have ported our recognizer to other languages than German (Italian, Slovak, Slovenian, Czech, English, Japanese). We found that some languages achieve a higher recognition performance with comparable tasks, and are thus easier for automatic speech recognition than others. Furthermore, we present experiments which show the performance of cross-lingual speech recognition of an untrained language with a recognizer trained with other languages. The substitution of phones is important for cross-lingual and simultaneous multilingual recognition. We compared results in cross-lingual recognition for different baseline systems and found that the number of shared acoustic units is very important for the performance. With simultaneous multilingual recognition, performance usually decreases compared to monolingual recognition. In few cases, like in the case of non-native speech, however, the recognition can be improved. (C) 2001 Elsevier Science B.V. All rights reserved.