In speech, acoustic cues are used to manifest a number of linguistic events including segmental phonemes and supra-segmental ones such as tones, prosodic phrasing structure, intonation, etc. It has been an interesting topic to quantitatively compare the importance of different linguistic events. However, previous studies have been mainly confined to segmental or segment-like units. No studies could be found to show quantitatively the importance of supra-segmental events of prosody boundaries. From the view of information transmission, both segmental and supra-segmental events make indispensable contributions to natural human speech communication. This paper presents a novel way to quantitatively estimate the information contribution of prosody boundaries, taking the same way to estimate those of segmental phonetic contrasts and syllable tones. Experiments were done using a Chinese newspaper text corpus and a conversation speech corpus. Preliminary results show that prosody boundaries carry much more information than phonetic segments. Hence, they are much more important than segments for human speech communication.

Index Terms: functional load, prosody boundary, mutual information, information contribution