Integrating Prosodics into a Language Model for Spoken Language Understanding of Thai

This paper describes a preliminary work on prosody modeling aspect of a spoken language understanding system for Thai. Specifically, the model is designed to integrate prosodics into a language model based on constraint dependency grammar. There are two steps involved, namely the prosodic annotation process and the prosodic disambiguation process. The annotation process uses prosodic information (stress, pause and syllable duration) obtained from the speech signal during low-level acoustic processing to encode each word in the parse graph with a prosodic feature called strength dynamic. The goal of the annotation process is to capture the correspondence between the phonological and phonetic attributes of the prosodic structure of utterances and their intended meanings. The prosodic disambiguation process involves the propagation of prosodic constraints designed to eliminate syntactic ambiguities of the input utterance. It is considered a pruning mechanism for the parser by using prosodic information. The aforementioned process has been tested on a set of ambiguous sentences, which represents various structural ambiguities involving five types of compounds in Thai.