Concatenative speech synthesis for Amharic using unit selection method
Eyob B. Kasie, Yaregal Assabie · 2012
In this paper we propose algorithms and methods that address critical issues in developing a general Amharic text-to-speech synthesizer. Converting grapheme to phoneme in Amharic is a very challenging task because of the two necessary and yet orthographically unrepresented components of the language -- epenthesis and gemination. Modeling prosodic features of various speaking styles is also the other challenging task in developing Amharic TTS. Making use of orthographic property of verbs in their perfect form, this work introduces set of rules that can be used to locate phones that need to be stressed and algorithm that inserts epenthetic vowel wherever necessary. This paper also presents methods to represent intonations that vary according to punctuation marks ("?" and "#") and phoneme location. In addition to these issues we also introduce transliteration rule for numbers and phone labeling scheme that captures allophonic variations in regard to gemination, epenthesis, and declarative versus judgment request intonations. The system is evaluated for naturalness and intelligibility by ten fluent speakers of the language and experimental results are reported.