Editing Vocoder Development (section)

== Historical Context ==
Speech synthesis, commonly known as Text-to-Speech (TTS), has gained increasing importance in people's lives. The development of TTS technology spans centuries, beginning with the Mechanical and Electro-Mechanical Era which relied on mechanical and electro-mechanical components to simulate speech sounds. It progressed through the Electrical and Electronic Era, where electronic technology was used to create early formant synthesizers and speech coding systems, and eventually entered the digital and computational era, marked by the transition to digital signal processing and computational methods for speech synthesis.

==== '''Mechanical and Electro-Mechanical Era''' ====
This era commenced with early speech synthesis attempts in the late 18th century. In 1769, [[Wolfgang von Kempelen's Speaking Machine (1769)|Wolfgang von Kempelen]] engineered a mechanical speaking device that ingeniously emulated speech sounds through the mechanical simulation of vocal cords, vocal tracts, and lungs. Concurrently, [[Mechanical synthesis|Christian Kratzenstein]] embarked on early mechanical synthesis by employing five organ pipe-like resonators to successfully reproduce five distinct vowels. Later in 1824, [[Wheatstone's "Speaking Machine" (1824)|Wheatstone]] introduced a "Speaking Machine," and in 1846, Joseph Faber constructed "Euphonia," both utilizing a series of mechanical components to produce speech-like sounds. During this period, the mechanical and electro-mechanical era of speech synthesis was drawing to a close. 

Despite their constraints in generating an extensive vocabulary and sentences, these early endeavours made noteworthy contributions to the exploration of speech synthesis, igniting extensive research into the physiology of speech production and experimental phonetics. The comprehension of acoustic resonators, spectral components, and formants marked a pivotal shift toward the scientific investigation of human sound production, setting the stage for the subsequent era of speech synthesis <ref>Schroeder, M. R. (1993). A brief history of synthetic speech. Speech communication, 13(1-2), 231-237.</ref><ref name=":2">Story, B. H. (2019). History of speech synthesis. Teoksessa The Routledge Handbook of Phonetics, toimittaneet William F. Katz & Peter F. Assmann, 9-33.</ref>.

==== '''Electrical and Electronic Era''' ====
In the electrical and electronic era, Text-to-Speech (TTS) technology underwent a transformative evolution, with the convergence of electricity and emerging electronic components giving rise to more efficient speech synthesis systems. This era dates back to 1922 when John Q. Stewart designed a system utilizing early electronic technology to generate speech sounds, essentially introducing the first electrical formant synthesizer. Electronic speech coding was inaugurated by Homer Dudley in response to bandwidth limitations on telegraph cables and the substantial bandwidth requirements for transmitting spectral content. Dudley designed [[Voder]] in 1930 and later created the Vocoder in the 1940s, introducing the concept of analyzing speech into spectral components and synthesizing it<ref name=":2" />. 

The Vocoder laid the foundation for subsequent TTS developments and paved the way for further research in the field of speech synthesis. However, the Vocoder had limitations in terms of naturalness and intelligibility in speech synthesis, primarily due to its complexity and dependence on manual tuning, making it challenging to achieve high-quality and versatile speech synthesis <ref name=":2" />.