  Cued Speech (CS) is a communication system developed for deaf people, which
exploits hand cues to complement speechreading at the phonetic level.
Currently, it is estimated that CS has been adapted to over 60 languages;
however, no official CS system is available for Mandarin Chinese. This article
proposes a novel and efficient Mandarin Chinese CS system, satisfying the main
criterion that the hand coding constitutes a complement to the lips movements.
We propose to code vowels [i, u, y] as semiconsonants when they are followed by
other Mandarin finals, which reduces the number of Mandarin finals to be coded
from 36 to 16. We establish a coherent similarity between Mandarin Chinese and
French vowels for the remaining 16 vowels, which allows us to take advantage of
the French CS system. Furthermore, by investigating the lips viseme
distribution based on a new corpus, an optimal allocation of the 16 Mandarin
vowels to different hand positions is obtained. A Gaussian classifier was used
to evaluate the average separability of different allocated vowel groups, which
gives 92.08\%, 92.33\%, and 92.73\% for the three speakers, respectively. The
consonants are mainly designed according to their similarities with the French
CS system, as well as some considerations on the special Mandarin consonants.
In our system, the tones of Mandarin are coded with head movements.
