Acoustic Differentiation of L- and L-L% in Switchboard and Radio News Speech

Acoustic evidence for a distinction between low-toned intermediate (ip) and intonational phrase (IP) boundaries is presented from two speech corpora representing spontaneous, conversational speech and scripted broadcast speech. Robust effects of the two boundary levels are found in the phrase-final syllable rime in both corpora. Nucleus duration is longer and the F0 value at rime end is lower at IP boundaries compared to ip boundaries. Glottalization is also more frequent before an IP boundary. Other effects of boundary level on the F0 and intensity contours over the phrase-final rime are evident but variable across the two corpora. These findings support the BeckmanPierrehumbert theory of intonation [1] in its recognition of two levels of prosodic phrasing.