Tangerine: a large vocabulary Mandarin dictation system

The text input for non-alphabetic languages, such as Chinese, has been a decades-long problem. Chinese Dictation using large vocabulary speech recognition provides a convenient mode of text entry. In contrast to a character based Dictation system [5], a word-based Mandarin dictation system has been designed [3] (based on Apple's PlainTalk speech recognition technology [4]) for efficient entry of Chinese characters into a computer. In this paper new features and improvements to the dictation system are presented. The new features and improvements have produced an overall reduction in recognition error of 50 80%. The vocabulary has also been increased from 5000 words to over 11,000 words. The new features are:mel frequency Cepstral analysis, spectral noise subtraction, cepstral mean normalisation, HMM based tone classification, training data reduction, adaptive training, more detailed sub-syllable modeling and a statistical language model.