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<Paper uid="P06-2125">
  <Title>Sydney, July 2006. c(c)2006 Association for Computational Linguistics An HMM-Based Approach to Automatic Phrasing for Mandarin Textto-Speech Synthesis</Title>
  <Section position="4" start_page="0" end_page="977" type="relat">
    <SectionTitle>
2 Related Work
</SectionTitle>
    <Paragraph position="0"> Automatic prediction of prosodic phrase is a complex task. There are two reasons for this conclusion. One is that there is no explicit relationship between text and phonetic features.</Paragraph>
    <Paragraph position="1"> The other lies in the ambiguity of word segmentation, POS tagging and parsing in the Chinese natural language processing. As a result, the input information for the prediction of prosodic phrase is quite &amp;quot;noisy&amp;quot;. We can find that most of published methods, including (Chen et al., 1996; Chen et al., 2000; Chou et al., 1996; Chou et al., 1997; Gu et al., 2000; Hu et al., 2000; Lv et al., 2001; Qian et al., 2001; Ying and Shi, 2001) do not make use of high-level syntactic features due to two reasons. Firstly, it is very challenging to parse Chinese sentence because no grammar is formal enough to be applied to Chinese parsing. In addition, lack of  morphologies also causes many problems in parsing. Secondly, the syntactic structure is not isomorphic to the prosodic phrase structure.</Paragraph>
    <Paragraph position="2"> Prosodic phrasing remains an open task in the Chinese speech generation. In summary, all the known methods depend on POS features more or less.</Paragraph>
  </Section>
class="xml-element"></Paper>