The rule-based parsing is a prevalent method for the natural language understanding (NLU) and has been introduced in dialogue systems for spoken language processing (SLP). However, additional measures must be taken to cope with the severe spoken linguistic phenomena, such as garbage, repetition, ellipsis, word disordering, fragment and ill form, which frequently occur in the spoken language. We propose in this paper a robust parsing scheme, which integrates the following methods. Keywords are used as terminal symbols; hence the symbol set of the grammar is purely within the semantical category. The definition of the grammar is extended to accommodate four types of rules, called up-tying, by-passing, up-messing, and over-crossing respectively. An improved chart parser, named marionette, is designed to parse the semantic grammar instance. The robust parsing scheme has been adopted in an air traveling information service system, called EasyFlight, and has achieved a high performance when dealing with the spontaneous speech.

Full Paper

Bibliographic reference.  Yan, Pengju / Zheng, Fang / Xu, Mingxing (2001): "Robust parsing in spoken dialogue systems", In EUROSPEECH-2001, 2149-2152.