Diachronic contrastive analysis on read speech in broadcast news: Evidence from pitch and duration

Which diachronic phonetic changes happened in Mandarin Chinese by the past 100 years? This paper intends to analyze and compare the pitch and duration of read speech in broadcast news from a diachronic perspective. The research results show that the peaks of pitch are the highest, the pitch range is the widest in the 1970s, especially the upraising of the valleys of pitch are so frequent; and the 1950-60s is the second; during the three periods of 1980s, 1990s and 2000s, the peaks of the pitch gradually drift down and the pitch range becomes narrowed. The average word speed of the 1970s is the slowest, and the duration of syllables is the longest; and the 1950-60s is the second; during the other three periods, word speed speeds up and the duration of syllables becomes shortened. Furthermore, the prosodic features are not determined by the text in the different historical periods.