Milestones:Speak & Spell, the First Use of a Digital Signal Processing IC for Speech Generation, 1978


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Speak & Spell, the First Use of a Digital Signal Processing IC for Speech Generation, 1978

In December 1976, Richard Wiggins demonstrated the Speak & Spell concept to Paul Breedlove, Larry Brantingham and Gene Frantz in Texas Instruments' Dallas research laboratory. This group led the team that created Speak & Spell in April 1978. The key device was the industry's first digital signal processing integrated processor, the TMS5100. This innovation in audio processing began the huge digital signal processing consumer market.

The milestone plaque may be viewed at the Texas Instruments North Campus, 13532 North Central Expressway, Dallas, TX, U.S.A.

The Speak & Spell introduced the first single chip Digital signal processor for generating speech using linear predictive coding (LPC). It was the first of a three-part talking educational toy series that also included Speak & Read and Speak & Math. It started with the Texas Instruments linear predictive coding (LPC) Speech Chip TMS5100 (internally coded TMC0280), which is the earliest digital signal processing chip in the industry. Speak & Spell helped teach millions of children how to spell. It make its way to Hollywood, to the covers of Business Week and finally to the Smithsonian Institution Museum.

The speak and Spell digital signal processing (DSP) innovation in audio processing is the starting milestone for the huge digital signal processing industry that has a more than $20 Billion market today. The ideal of using digital signal processing has grown tremendously with the development of analog to digital and digital to analog conversion chips and techniques. Digital signal processors are used in many of the consumer, industrial, and military applications:

  • wireless communications and cellular phones
  • audio and speech signal processing
  • video and game machines
  • digital cameras and digital TVs
  • motion control and engine control
  • medical diagnostic imaging
  • sonar and radar signal processing
  • sensors and actuators
  • seismic exploration and weather forecasting

In early 1978, Texas Instruments introduced the industry’s first linear predictive coding digital signal processor IC, TMS5100, internally code named TMC0280, which was used in the Speak and Spell products. It is developed from one of the other Texas Instruments inventions of the computer-on-a-chip, also known as the single-chip microcontroller. The Speak and Spell circuit and system design made it suitable for consumer products and created an industry of digital signal processors inside and outside of TI and applications of digital signal processing well beyond the initial audio and speech processing.

The Speak and spell series of learning aid used an entirely new concept in speech recognition than tape recorders and pull-string photograph records used in many “speaking” toys at the time. TI's Solid State Speech circuitry had no moving parts. When it was told to say something it drew a word from the memory, processed through an integrated circuit model of a human vocal tract and then generated electronically. It marked the first time the human vocal tract had been electronically duplicated on a single chip of silicon with signal processing applications.

Speak & Spell, Speak & Math™, Speak & Read™, Speak & Music™, and a whole collection of speaking children's toys, were produced around the world in several languages in many years. The basic learning principles and design concepts remain the standard for educational toys.

Speech synthesis and voice recognition applications are pervasive today – ranging from telephone answering applications for making business scheduling system, checking airline schedules, checking bank balance, to voice-assisted navigation systems in automobiles, computers for the blind, and voice activated security applications.

Digital signal processing has become the most significant innovation that includes integrated circuits and systems design and signal processing algorithms and applications. This has been influencing human kind from the initial audio and speech processing to video and graphics processing, to machine control and automation, and to communications and image processing. Mordern wireless communications is the best embodyment of digital signal processing technology that made clear audio, clear video transmissions a reality.

Digital signal processing has connected the analog world with the digital world much tighter and closer for the world we live in.

List of supporting documents and publications submitted in electronic format

Speak and Spell is documented as one of the many innovations throughout Texas Instruments, Inc.’s historic contributions to science and engineering that impacted the world:

To view a history of TI innovations, visit

The Smithsonian Institution has a web page on the Speak & Spell with some photos of a preproduction unit that was built for the Summer Consumer Electronics Show

Speak & Spell on the Texas Instruments, Inc. Website

Wikipedia Speak & Spell information

Here are a few of the significant inventions for the product concept, the synthesis device, and keyboard input.

  • US Patent 4,516,260: Electronic learning aid or game having synthesized speech
  • US Patent 4,209,836: Speech synthesis integrated circuit device
  • US Patent 4,188,626: Method for scanning a keyboard and for actuating a display device via common conductors
  • US Patent 4,331,836: Speech synthesis integrated circuit device
  • US Patent 4,398,059: Speech producing system
  • US Patent 4,357,489: Low voltage speech synthesis system with pulse width digital-to-analog converter


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