Modeling Taiwanese Southern-Min Tone Sandhi Using Rule-Based Methods

A sizable corpus of Taiwanese text in Latin script has been accumulated over the past two hundred or so years. However, due to the special status of Taiwan, few people can read these materials at present. It is regrettable that the utilization of these plentiful materials is very low. This paper addresses problems raised in the Taiwanese Southern-Min tone sandhi system by describing a set of computational rules to approximate this system, as well as the results obtained from its implementation. Using the romanized Taiwanese Southern-Min text as source, we take the sentence as the unit, translate every word into Chinese via an online Taiwanese-Chinese dictionary (OTCD), and obtain the part-of-speech (POS) information from the Chinese Electronic Dictionary (CED) made by the Chinese Knowledge and Information Processing (CKIP) group of Academia Sinica. By using the POS data and tone sandhi rules based on linguistics, we then tag each syllable with its post-sandhi tone marker. Finally, we implement a Taiwanese Southern-Min tone sandhi processing system which takes a romanized sentence as an input and then outputs the tone markers. Our system achieves 97.39% and 88.98% accuracy rates with training and test data, respectively. Finally, we analyze the factors influencing error for the purpose of future improvement.