Temporal stability of long-term measures of fundamental frequency

We investigated long-term mean, median and base value of F0 to estimate how long it takes their variability to stabilize. Change point analysis was used to locate stabilization points. In one experiment, stabilization points were calculated in recordings of the same text spoken in 26 languages. Average stabilization points are 5 seconds for base value and 10 seconds for mean and median. Variance after the stabilization point was reduced around 40 times for mean and median and more than 100 times for the base value. In another experiment, four speakers read two different texts each. Stabilization points for the same speaker across the texts do not exactly coincide as would be ideally expected. Average change point dislocation is 2.5 seconds for the base value, 3.4 for the median and 9.5 for the mean. After stabilization, individual differences in the three measures obtained from the two texts are 2% on average. Present results show that stabilization points in long-term measures of F0 occur earlier than suggested in the previous literature. Index Terms: fundamental frequency, long term measurements, forensic phonetics