Of the 5 pitch-phenomena contained in Y. R. Chao’s framework of Mandarin Chinese intonation, the phenomenon termed ‘successive tonal addition’ has proved highly elusive. Using communicatively-based spontaneous speech samples, the first instrumental evidence of successive tonal addition is presented here, found to consist of nonlexical pitch-movements added to the lexical tones of utterance-final syllables. Investigation into the functions of these phenomena, referred to as ‘edge tones’, showed these to be affective in nature, signalling emotio-attitudinal messages.