Recognize tone languages using pitch information on the main vowel of each syllable

An innovative method for speech recognition of tone languages is reported. By definition, the tone of a syllable is determined by the pitch contour of the entire syllable. We propose that the pitch information on the main vowel of a syllable is sufficient to determine the tone of that syllable. Therefore, to recognize tone languages, only main vowels are needed to associate with tones. The number of basic phonetic units required to recognize tone languages is greatly reduced. We then report experimental results on Cantonese and Mandarin. In both cases, using the main vowel method, while the number of phonemes and the quantity of training data are substantially reduced, the decoding accuracy is improved over other methods. Possible applications of the method to other tone languages, including Thai, Vietnamese, Japanese, Swedish, and Norwegian are discussed