Speech recognition of foreign out-of-vocabulary words using a hierarchical language model

Hirofumi Yamamoto, Genichiro Kikui, Satoshi Nakamura, Yoshinori Sagisaka

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    This paper proposes a new speech recognition scheme for foreign out-of-vocabulary words embedded in native-language speech. To recognize foreign names frequently observed in news speech or in translation speech, we adopted a hierarchical language model that had been successfully applied to OOV words covering native vocabularies. In this hierarchical language model, OOV vocabularies are modeled as a word-class model in the upper-layered model, and their statistical phonotactic constraints are modeled in the lower-layered model. Since extra statistics are needed to cover foreign words and their pronunciation differences, we have introduced two techniques. The first is to combine translation target language models and translation source statistics of OOVs using the hierarchical language model. The second is to automatically generate recognition target pronunciations from original pronunciations by syllable-to-syllable mapping. To confirm the validity of this recognition scheme, we have conducted speech recognition experiments using English speech including Japanese personal names as OOV words. The proposed method outperformed the existing algorithm using a lexicon consisting of all the words in the training set. Surprisingly, it achieved better OOV recognition results than the non-OOV condition where all the proper names in the test set are registered in the lexicon.

    Original languageEnglish
    Title of host publicationINTERSPEECH 2006 and 9th International Conference on Spoken Language Processing, INTERSPEECH 2006 - ICSLP
    Pages1870-1873
    Number of pages4
    Volume4
    Publication statusPublished - 2006
    EventINTERSPEECH 2006 and 9th International Conference on Spoken Language Processing, INTERSPEECH 2006 - ICSLP - Pittsburgh, PA
    Duration: 2006 Sep 172006 Sep 21

    Other

    OtherINTERSPEECH 2006 and 9th International Conference on Spoken Language Processing, INTERSPEECH 2006 - ICSLP
    CityPittsburgh, PA
    Period06/9/1706/9/21

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    Keywords

    • Foreign word
    • Hierarchical language model
    • Language model
    • Out-of-vocabulalry word
    • Speech recognition

    ASJC Scopus subject areas

    • Computer Science(all)

    Cite this

    Yamamoto, H., Kikui, G., Nakamura, S., & Sagisaka, Y. (2006). Speech recognition of foreign out-of-vocabulary words using a hierarchical language model. In INTERSPEECH 2006 and 9th International Conference on Spoken Language Processing, INTERSPEECH 2006 - ICSLP (Vol. 4, pp. 1870-1873)