Rule Synthesis of Simple English Sentences

Abstract

Simple English sentences were generated by concatenating words spoken in isolation with minimum modifications of the synthesis parameters. The sentence forms were: Article-(adjective)-subject-verb-article-(adjective)-object. The two adjectives may or may not be present. A dictionary of 266 words specified by formant data with the duration of the words adjusted by linear interpolation to a reasonable duration for connected speech was stored. Pitch rules for the different sentences were derived from an average sentence pitch contour. Words were concatenated with no further duration adjustment, and formant smoothing was applied only at voiced adjacencies for one set of data of both the preceding and the following words; the pitch, however, was replaced by the rule pitch. The rule-generated sentences were compared with sentences obtained from formant analysis-synthesis of naturally spoken sentences, rather than with the naturally spoken sentences themselves, because formant analysis-synthesis introduces a characteristic nonnatural quality that is not a consequence of the rule-prosody. These comparisons demonstrated that the quality of the rule concatenated sentences is comparable to the quality of the resynthesized speech.