A method for synthesizing Arabic speech has been developed which uses a reasonably sized set of subphonetic elements as the synthesis units to allow synthesis of unlimited-vocabulary speech of good quality. The synthesis units have been defined after a careful study of the phonetic properties of modern standard Arabic, and they consist of central steady-state portions of vowels, central steady-state portions of consonants, vowel-consonant and consonant-vowel transitions, and some allophones. A text-to-speech system which uses this method has also been developed. The input of the system is ordinary Arabic spelling with diacritics and/or simple numeric expressions. Synthesis is controlled by several text-to-speech rules which are formulated and developed as algorithms more suited for computer handling of the synthesis process. The rules are required for converting the input text into phonemes, converting the phonemes into phonetic units, generating the synthesis units from the phonetic units, and concatenating the synthesis units to form spoken messages. The suitability of the method for synthesizing Arabic has been shown by realizing all its functions on a personal computer and by conducting understandability test on synthesized speech. >
['Yousif A. El-Imam']
An unrestricted vocabulary Arabic speech synthesis system