a website collaboration between Science Service and the Smithsonian Institution

1939 - young lady striking keys is creating a man-like voice
with a cross reference on this site


CD 1966099 E&MP37.001

Electric Speech

Jan. 1939

The young lady striking keys is creating a man-like voice. This new synthetic orator will "lecture" with his "electrical accent" at the New York and San Francisco world fairs. It is a compact machine resting on a small table, plus as many loudspeakers as are necessary to reach the audience.

VODER, THE MACHINE THAT TALKS. No recording of any kind is used in this latest addition to the anatomy of the Mechanical Man. A girl at a keyboard controlling varying electrical currents does the trick.

It has a pair of keyboard units, more than a dozen other controls and an electrical circuit featuring a vaccum (sic) tube and a gas-filled discharge tube.

Seated at the keyboard of the “Voder”, this young lady can carry on an ordinary conversation by pressing keys in the Bell Telephone Laboratories exhibit in the Palace of Electricity and Communication at the California World’s Fair which will have its premiere February 18 and 19.

A pedal operated by her right foot enables the operator to make voice inflection, and synthesized speech is heard from a loudspeaker. The “Voder” is a highlight of the telephone exhibit. (GOLDEN GATE INTERNATIONAL EXPOSITION)

additional text found:


A close-up of “Pedro, the Voder”, feature attraction of the Bell Telephone Laboratories exhibit at the Golden Gate International Exposition. The ten white keys control speech sound; the eleventh is volume control, and the three black produce the sound of “stop” consonants. Under the operator’s left wrist is a switch which changes over from consonants to vowels, thus producing synthesized speech and the operator of this part of the exhibit can carry on an ordinary conversation with you (mechanically) at the fair. The exhibit is housed in the Palace of Communications and Electricity.

Cross reference on this site...
  • January 14, 1939 cover

  • original issue - 16 page thumbnail selection

  • page 19 - full feature story

  • Original Caption by Science Service
    ©Bell Telephone

    Comments: June 4, 2000

    It is wonderful that you have taken the time to document the Voder device. It was especially exciting to see the readable image of the Science News Letter article of 1939. I remember reading about this device as a child (the 1950's), however, most libraries have "cleaned out" a lot of their old technology books and it is hard to find material any more.

    Fortunately your site is keeping this technology accessible! Robert Matteson

    We hope to gather valid information to cross reference our material. However, we cannot change the existing Science Service caption, though we can include corrections, comments and sources for expanding the information on our image presentation.

    Thank You!
    Science Service Historical Image Collection Webmaster

    The Harriet Green-Kopp Papers
    to review this collection contact: NMAH AC#1130

    Collection Synopsis June 3, 2008 - Bailey Ball, Intern 2007-2008
    National Museum of American History - Information Technology and Communications


    The following collection pertains to voiceprint technology for the deaf and specifically preserves the vestiges of the many accomplishments of Dr. Harriet Green Kopp (1917 - February 11, 2007).

    Historical Note

    As a young, unmarried woman, Harriet Green began her career assisting on research at Bell Laboratories in Murray Hill, New Jersey in the early 1940s. Here she primarily worked with Dr. Ralph K. Potter and Dr. George Adams Kopp, the man who would eventually become her husband, on a project meant to develop practical use for a machine that would represent visible speech for the deaf and could be manufactured for consumption on a mass scale for everyday use.

    Dr. Potter and his team, including Dr. Harriet Green Kopp, who was then formally known as Miss Harriet Green, were among the first to discover the usefulness of the graphic portrayal of sound. George Kopp and Harriet Green worked at Bell Laboratories from 1943 through 1946. During that time, they "collaborated in modification of the sound spectrograph, developed the visible speech phonetic alphabet, analyzed and defined syllabic transitions, [and] made basic aspect-ratio and other visual portrayal decisions to establish form of visual representation" i among other things.

    While at Bell Labs, Potter, Green, and Kopp worked on Voice Print Identification procedures that focused on developing technology which would provide a visual interpretation of speech. While hearing persons acquire their oral communication skills through auditory feedback by interacting with their hearing peers, deaf and hearing impaired individuals lack the means to develop these skills on their own and often meet language acquisition with limited success. ii Miss Green and her colleagues developed a desire to develop and harness a machine technology in order to utilize visible speech for a variety of purposes, mainly in providing a way to assist these deaf individuals in their communications skills.

    Potter, Kopp, and Green worked mainly with the sound spectrograph, a machine which visually represented sound waves displaying the parameters of frequency, intensity, and time in charts which came to be known as spectrograms. The research on this machine was conducted from the years 1939 through 1944. Trained personnel worked to help deaf subjects use visible speech in order to develop and perfect this method. Sound waves depicted visually were used to portray these parameters to a deaf individual's functioning sense of sight. In this way, the deaf can develop speech that is more akin to normal speech and will be more useful to them socially.

    The sound spectrograph's technology was later recognized by the military during World War II as a possible means for decoding intercepted enemy audio messages which had been encrypted. The technique was not harnessed for this purpose before the end of the war, but the influence of the sound spectrograph's technology had a lasting effect on visible speech representation and subsequent methods for developing speech for the deaf. Potter, Kopp, and Green later published their work in a book Visible Speech, published by the D. Van Nostrand Company of New York in 1947.

    From Bell Labs, Harriet Green, Dr. George A. Kopp, and Dr. Ralph K. Potter moved on to continue working together and joined in what was entitled the Visible Speech Research Program, a University of Michigan Study, which was proposed and conducted from 1946-1948. Bell Labs loaned the cathode ray tube, another visible speech device developed to be more instantaneous, first to University of Michigan and then to the Rackham School of Special Education in Eastern Michigan to allow the Kopps to study and evaluate this equipment. Here the Kopps conducted a similar study using deaf children to attempt to harness this technology to enhance the intelligibility of their speech. However, the number of children, teachers, and funds were insufficient to draw definitive conclusions iii.

    Harriet Green and George Adams Kopp continued to devote their lives to the development of visible speech technology and through a series of grants, conducted more research projects. This included an investigation conducted at Wayne State University in Detroit, Michigan to continue the work George Kopp had conducted in Ann Arbor and Ypsilanti, Michigan regarding the usefulness of the visible speech cathode ray tube translator as a supplement to the oral method of teaching speech to deaf and severely deafened children.

    Beyond to her involvement in these research projects, Harriet Green Kopp held numerous teaching positions throughout her career. These include positions at Brooklyn College, Indiana University, as well as Michigan State University. After many years in teaching, in February 1959, Dr. Harriet Green Kopp obtained a position as the headmaster of the Detroit Day School for the Deaf where the cathode ray tube translator was ultimately moved to this school's Speech and Hearing Clinic for Dr. Green Kopp to continue her work with the device. From the Detroit Day School for the Deaf, Harriet Green Kopp spent the last years of her teaching career at San Diego State University (1973-1980) where she was Professor Emeritus in the school of Speech, Language, and Hearing Sciences. Dr. Harriet Green Kopp died of an illness on February 11, 2007.

    The Green-Kopp Papers Collection includes 130 indexed files containing documents which chronicle the life, career and many accomplishments of Dr. Harriet Green-Kopp. It contains documents, images, and books of a woman who herself suffered no hearing disabilities, but nevertheless showed a dedication to the education and welfare of such individuals.

    Descriptive Entry

    The Green-Kopp Collection includes documentary evidence of Dr. Harriet Green-Kopp's accomplishments during her professional career. This collection contains extensive information and thorough notes with updates regarding the grants and projects Dr. Green-Kopp was involved in during her work at Bell Labs, the study she helped to conduct at the University of Michigan and much more.

    The majority of career-related documents are from the work Dr. Green-Kopp completed at Bell Telephone Laboratories in Murray Hill, New Jersey. They include notes on the Visual Telephony Conferences (Box 1, File 11), subjects' spectrograms (Box 1, File 12), the Voice Print Identification procedure and information (Box 1, Files 13-15), research reports on recordings in various languages including English and Chinese, and Bell Laboratories daily logbooks which provide notes on the Visible Speech Project's daily proceedings from 1944-1946 (Box 2, File 8; Box 2, File 11).

    At the University of Michigan beginning in 1947 Harriet Green worked with her future husband Dr. George Adams Kopp and his research associate Dr. Ralph K. Potter in conducting the Visible Speech Research Program. Documents pertaining to this project include correspondence between the Project's Advisory Committee and other individuals involved, including Ralph Potter, George Kopp, Harlan Bloomer, Clark Tibbits, RR. Riesz, Robert Essig, Frances Lord, Hans Kurath, Lloyd Woodburne, Louise Howell, Harley Magee, and Clarence V. Hudgins (Box 2, File 15), a progress report presented at the American Speech Correction Conference (Box 2, File 16), a report on how funding continued the project at Ypsilanti (Box 3, File 1), the logistics for the operation of the Visible Speech Research Program (Box 3, File 4) and the project's final report (Box 3, File 5).

    Also included is extensive documentation of the grant requests and renewals which started and continued these projects. A grant awarded to Dr. Harriet Green-Kopp along with her husband Dr. George Kopp and her research associate Dr. Ralph K. Potter in 1963: research grant #RD-526, partially funded by the Federal Office of Health Education and Welfare. With this funding, Dr. Green-Kopp and her partners conducted an evaluation of the usefulness of the visible speech cathode ray tube translator as a supplement to the oral method of teaching speech to deaf and severely deafened children at the Wayne State University Speech and Hearing Clinic. Documents pertaining to grant# RD-526 include a progress report (Box 3, File 30), and a draft of the grant's final report (Box 4, Files 1-2). This research was consolidated in what eventually became the book Visible Speech for the Deaf (Kopp, George and Harriet Kopp. Detroit: Wayne State University Hearing and Speech Association, 1963)

    This collection also contains documents pertaining to Dr. Harriet Green-Kopp's education and certifications. Examples include her diploma from Brooklyn College, issued June 1, 1937 (Box 1, File 3), her thesis completed as part of the requirements for her Master of Arts degree from Brooklyn College, issued in 1940, entitled "A Study of the Speech of 411 Acoustically Handicapped Children in the New York City Public Schools" (Box 1, File 4), as well as the doctoral dissertation she completed in order to receive her PhD from Teacher's College, Columbia University in 1963 entitled "Eye Movements in Reading as Related to Speech Dysfunction in Male Stutterers" (Box 3, File 33).

    The collection provides documents such as course syllabi that represent Dr. Green-Kopp's transition into a long career in teaching where she began to educate students of her own. These include a lecture and seminar notes from 1957-1966 (Box 3, File 26), information on her career at the Detroit Day School for the Deaf (Box 3, File 32), the report she wrote to the Detroit Board of Education regarding the Day School for the Deaf (Box 4, File 5), and her retirement papers from the Detroit Day School for the Deaf (Box 5, File 8).
    In addition to Visible Speech (1947), the collection also includes numerous other books authored or co-authored by Harriet Green Kopp herself. These include Some Functional Applications of Basic Phonetic Principles by Harriet Green Kopp (1948) and Basic Phonetic Principles for the Classroom Teacher by George A. Kopp and Harriet G. Kopp (1950). Also included is an example of a book which exhibits the legacy of Dr. Harriet Green-Kopp and Dr. George Kopp's work, Therapy for Young Stutterers: The Kopp Method by Ellwood G. Anderson (1970).

    The Green-Kopp collection houses 215 images, 60 lantern slides, 30 35MM slides, and 5 blueprints. This portion of the collection offers a vast array of images including many of Dr. Kopp herself, her associates at Bell Laboratories, her subsequent work, and many of the equipment she worked with as well as the procedures she developed throughout her career. Particularly interesting are the detailed blueprints of the sound spectrograph itself, offering an intricate portrayal of the inner workings of this fascinating piece of technology.

    Besides the documents of her professional work, the Green-Kopp collection also includes documents which reveal aspects of Dr. Harriet Green-Kopp's life outside of her career, including examples of her personal correspondence with friends and co-workers.

    i Potter, R.K., G.A.Kopp, and Harriet C. Green. Visible Speech. New York: D. Van Nostrand, 1947, 4.
    ii Kopp, George and Harriet Green Kopp. Visible Speech for the Deaf. Detroit: Wayne State University Hearing and Speech Association, 1963, 1.
    iii Ibid., 3.

    COLLOQUIUM June 3, 2008
    :"A History of the Sound Spectrograph: Deafness, Feedback and Information Theory"
    Mara Mills - Doctoral Candidate, Harvard University
    Former Lemelson Fellow, National Museum of American History

    June 25, 2008 ABSTRACT:

    Bell engineers built a sound spectrograph in support of cryptanalysis during World War II. This technology for the graphic inscription of sound waves was the first to adequately portray the harmonics contained within speech.

    Spectrograms revealed the coding of telephone speech: temporal inversion, time-division scrambling, masking with noise, or the shuffling of frequency bands. From the outset, the spectrograph was also intended to support deaf oral education and visual telephony.

    After the war, the sound spectrograph (or sonograph) was adopted by communication ecology, linguistics, cardiology, and the field of audio editing. At Bell Labs, spectrograms became tools for research into the physical and statistical characteristics of spoken English. John Pierce, engineer and science fiction author, named this technology as one of the "most contributive" influences on information theory; it helped bring probability theory to the problem of efficient encoding.

    This talk focuses on the work of Harriet Green, who was hired in 1943 to co-coordinate the Visual Telephony aspect of the project--and who was the only woman on the technical staff at the time. With the assistance of the American Institute of Physics, I was able to interview Green and bring her manuscripts to the NMAH last year. These include: laboratory notebooks, spectrograms, and slides; formerly classified reports on voiceprint identification; proposals for automatic speech recognition and visual telephony; materials related to Edgar Bloom, a deaf engineer hired to assist with the project.

    National Museum of American History


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