SIGNIFICANCE OF KNOWLEDGE SOURCES OR A TEXT-TO-SPEECH SYSTEM FOR INDIAN LANGUAGES

This paper discusses the significance of segmental and prosodic knowle dge sources for developing a text-to-speech system for Indian language s. Acoustic parameters such as linear prediction coefficients, formant s, pitch and gain are prestored for the basic speech sound units corre sponding to the orthographic characters of Hindi. The parameters are c oncatenated based on the input text. These parameters are modified by stored knowledge sources corresponding to coarticulation, duration and intonation. The coarticulation rules specify the pattern of joining t he basic units. The duration rules modify the inherent duration of the basic units based on the linguistic context in which the units occur. The intonation rules specify the overall pitch contour for the uttera nce (declination or rising contour), fall-rise patterns, resetting phe nomena and inherent fundamental frequency of vowels. Appropriate pause s between syntactic units are specified to enhance intelligibility and naturalness.