This paper presents a Chinese text-to-speech system which aims to produce highly intelligible standard Chinese speech with natural sounding intonation from Pinyin text, using the LSI parallel formant speech synthesizer. Two specific features of the system are: the use of a demisyllable dictionary which permits an effective and reliable way of carrying out text to phonetic element conversion and the implementation of a flexible intonation framework which enables a very wide variety of natural sounding fundamental frequency (F0) contours to be generated automatically. Some evaluation data obtained from a syllable intelligibility test are provided.