<p class="first" id="d5180228e51">The automatic conversion of English text to synthetic
speech is presently being performed,
remarkably well, by a number of laboratory systems and commercial devices. Progress
in this area has been made possible by advances in linguistic theory, acoustic-phonetic
characterization of English sound patterns, perceptual psychology, mathematical modeling
of speech production, structured programming, and computer hardware design. This review
traces the early work on the development of speech synthesizers, discovery of minimal
acoustic cues for phonetic contrasts, evolution of phonemic rule programs, incorporation
of prosodic rules, and formulation of techniques for text analysis. Examples of rules
are used liberally to illustrate the state of the art. Many of the examples are taken
from Klattalk, a text-to-speech system developed by the author. A number of scientific
problems are identified that prevent current systems from achieving the goal of completely
human-sounding speech. While the emphasis is on rule programs that drive a format
synthesizer, alternatives such as articulatory synthesis and waveform concatenation
are also reviewed. An extensive bibliography has been assembled to show both the breadth
of synthesis activity and the wealth of phenomena covered by rules in the best of
these programs. A recording of selected examples of the historical development of
synthetic speech, enclosed as a 33 1/3-rpm record, is described in the Appendix.
</p>