Methods for generating pitch and duration contours in a text to speech

Abstract

A method for automatically generating pitch contours in a text to speech (TtS) system, the system converting input text into an output acoustic signal simulating natural speech, the method comprising the steps of: storing a plurality of associated stress and pitch level pairs, each of the plurality of pairs including a lexical stress level and a pitch level; calculating lexical stress levels of the input text; comparing the stress levels of the input text to the stored stress levels of the plurality of associated stress and pitch level pairs to find the stored stress levels closest to the stress levels of the input text; and copying the pitch levels associated with the closest stored stress levels of the stress and pitch level pairs to generate the pitch contours of the input text. Features illustrative of various modes of the invention include stress and pitch level pairs that correspond with the end of vowels, use of a phonetic dictionary to expand words to phonemes and concatenate stress levels, blocking sentences and the stress contours into constant or variable lengths by segmenting from the ends toward the beginnings, and averaging at the block boundary. The method may distinguish among declarations, questions, and exclamations. Training text may be collected from more than one speaker and scaled; the speaker(s) may wear a laryngograph to provide vocal cord activity.