We have previously demonstrated that tone modeling improved speech recognition on a
digit corpus [7]. In this work, we further improve tone recognition by normalizing for both tone
coarticulation and intonation effects. The tone classification errors on continuous digit strings
were reduced by 26.1% from the baseline, when the effects of ¼ downdrift, phrase boundary
and tone coarticulation were normalized. We also applied the same approach to
conversational speech from the YINHE domain [6], and obtained similar improvements. The …