College of Natural and Computational Sciences

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Browsing College of Natural and Computational Sciences by Subject "(NSWs)"

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    A Generalized Approach to Amharic Text-To-Speech (Tts) Synthesis System
    (Addis Ababa University, 2010-07) Tafere, Alula; Meshesha, Million (PhD)
    A text-to-speech (TTS) synthesis converts natural language text into speech. However, written text of a language contains both standard words (SWs) and nonstandard words (NSWs) like numbers, abbreviations, synonyms, currency, and dates. These NSWs cannot be detected by an application of “letter-to-sound” rule. This study describes generalized Amharic Text-To-Speech (TTS) synthesis, which attempt to handle both Amharic SWs and NSWs. The system is developed using speech synthesis framework of Festival, based on diphone unit concatenative synthesis by applying RELP coding technique. The model described in this work has two major parts: Natural language processing (NLP) and Digital language processing (DSP). The NLP handles the text analysis (transcription of the input SWs and NSWs) and extraction of the speech parameters. The DSP further enable to generate the artificial speech. Finally, the performance of the system shows that on the average 73.35% words both SWs and NSWs correctly pronounced. In addition, an assessment of intelligibility and naturalness of synthesized speech using MOS testing techniques results a score of 3 and 2.83, respectively. The experiment shows a promising result to design an applicable system that synthesis both SWs and NSWs for unrestricted text of a language. But, still there are areas need further investigations. Thoughtfulness of all type of NSWs and those ambiguities found in NSWs, while in test analysis block, using statistical technique to handle them based on their context. In addition, construction of part of speech POS tag-sets, tagger and tagged corpus for prosody analysis are also some areas that need further devotions. Keywords: Diphone concatenation, Speech Synthesis, (NSWs), RELP coding