Thai Grapheme-Based Speech Recognition

In this paper we present the results for building a grapheme-based speech recognition system for Thai. We experiment with different settings for the initial context independent system, different number of acoustic models and different contexts for the speech unit. In addition, we investigate the potential of an enhanced tree clustering method as a way of sharing parameters across models. We compare our system with two phoneme-based systems; one that uses a hand-crafted dictionary and another that uses an automatically generated dictionary. Experiment results show that the grapheme-based system with enhanced tree clustering outperforms the phoneme-based system using an automatically generated dictionary, and has comparable results to the phoneme-based system with the handcrafted dictionary.