Research of the pitch contour rules for an Italian language speech understanding system

The characterization of the influence of lexicon and syntax on the pitch contour in the Italian language is presented. The results of the work will be used in a Speech Understanding System for defining some constraints in the emission of hypotheses and for evaluating the likelihood that a synctatic structure can generate a given pattern of fundamental frequency. The pitch evolution is only determined in voiced tracts; then it is subdivided in a sequence of primitives and translated in symbols. Such strings of symbols are considered as sentences of a set regular languages, whose productions are learned using a stochastic inference procedure. Some results obtained from controlled experiments in which various factors are varied separately are presented.