The parsing program for automatic text-to-speech synthesis developed at the electrotechnical laboratory in 1968

The paper describes a parsing program developed at the Electrotechnical Laboratory, Tokyo, Japan, in 1968 for automatic speech synthesis from ordinary English spelling. The parser handles unique problems for a speech production system, especially of phrase-structure analysis in regard to stress and pause assignments. The parsing program consists of a dictionary of about 1500 most frequently used words, a simple syntactic analyzer and a breath-group delimiter. The syntactic analyzer, with the assistance of information stored in the dictionary, divides the sentence into phrases, and assigns pause markers at major syntactic boundaries; the breath-group delimiter decides actual pauses and sentence stress. The output of the parsing program consists of a sequence of phonemes with stress marks and of phrase termination marks. These letters and marks are transformed into vocal tract shapes, duration, and pitch signals in the subsequent part of the synthesis system. The parsing program, written in the PL/I language, consists of about 1900 statements.