F0 contours were obtained with a pitch tracking algorithm using an auto-correlation technique. The duration of the vowel preceding the boundary and also in certain word-internal positions has been measured. In order to characterize F0 movements, maximum and minimum values in the F0 contour observed before and after boundaries have been measured at vowel centers. Maxima were located in vowels showing an F0 value higher than the value at the preceding and following syllables. Accordingly, minima were located in vowels showing an F0 value lower than the value at the preceding and following syllables.
All vowels considered in the comparisons are non-prepausal and unstressed.
It can be seen from data in figure 1 that no significant differences have been found between the duration of vowels preceding the four types of syntactic boundaries. In order to assess the differences in duration between vowels located before a syntactic boundary and vowels which are not in this position, a comparison was made with a different group of vowels. Although no statistically significant differences appear, a tendency can be observed towards longer vowel durations when they occur in a syntactic boundary. F0 movements have been characterized in terms of the local shape of the F0 contour. Peaks and valleys adjacent to the boundary are used to define this contour.