This paper assesses the ability of a HMM-based speech synthesis systems to model the speech characteristics of various speaking styles1. A discrete/continuous HMM is presented to model the symbolic and acoustic speech characteristics of a speaking style. The proposed model is used to model the average characteristics of a speaking style that is shared among various speakers, depending on specific situations of speech communication. The evaluation consists of an identification experiment of 4 speaking styles based on delexicalized speech, and compared to a similar experiment on natural speech. The comparison is discussed and reveals that discrete/continuous HMM consistently models the speech characteristics of a speaking style.