Kenneth N. Stevens

Timeline

1. 1924–1948

   Engineering physics in Toronto

   Born in Toronto in 1924 to British-born parents, he earns bachelor's and master's degrees in engineering physics at the University of Toronto. After his master's, he stays at the university to teach returning soldiers under the Veterans Rehabilitation Act, among them his older brother, Pete.

2. 1948–1954

   A doctorate in Beranek's Acoustics Lab

   In 1948, he comes to MIT as a doctoral student in electrical engineering and works with Leo Beranek in the Acoustics Lab. His 1952 thesis, on the perception of sounds shaped by resonant circuits, goes before a committee that includes Beranek, J. C. R. Licklider and Walter A. Rosenblith. MIT adds him to its faculty in 1954.

3. 1953–1959

   Analysis by synthesis with Halle

   Gunnar Fant convinces him that a transmission-line model of the vocal tract is more flexible than a resonator model, and with S. Kasowski they publish "An electrical analog of the vocal tract" in 1953. In 1959, he and the MIT linguist Morris Halle publish "Analysis by Synthesis".

4. 1954–2007

   The Speech Communication Group

   As principal investigator of the Speech Communication Group in MIT's Research Laboratory of Electronics, he originates the quantal theory of speech, which explains why human speech uses only a small fraction of the sounds the vocal tract can produce. Much of the early work on speech synthesis and lexical access for speech recognition comes out of his lab through collaborations with Dennis Klatt and Victor Zue, and Klatt develops DECtalk as a member of the group. His retirement comes in 2007, at age 83, and over his career he advises more than 60 graduate students.

5. 1957–1977

   Full professor and LeBel chair

   MIT promotes him to associate professor in 1957 and to professor in 1963. On a 1962 sabbatical at KTH in Sweden, he works with Gunnar Fant and volunteers for cineradiography experiments, and the X-ray films he brings back form the basis for early work with Joseph Perkell. In 1977, he becomes Clarence J. LeBel Professor of Electrical Engineering and Computer Science.

6. 1963–1995

   Acoustical Society president and medals

   He serves on the executive council of the Acoustical Society of America from 1963 to 1966 and as its president from 1976 to 1977. The society awards him its Silver Medal in Speech Communication in 1983 and its Gold Medal in 1995.

7. 1998–2000

   Acoustic Phonetics and a National Medal

   In 1998, he publishes Acoustic Phonetics, a book that uses circuit analysis and signal processing to show how a discrete linguistic representation becomes the articulatory movements of speech. The 1999 National Medal of Science in engineering honors his speech research, which lays the groundwork for many speech synthesis and recognition technologies. President Bill Clinton presents the medal at the White House in March 2000.

8. 2004–2013

   Flanagan award and death in Oregon

   In 2004, he and Gunnar Fant become the joint first winners of the IEEE James L. Flanagan Speech and Audio Processing Award. He dies from complications of Alzheimer's disease in Clackamas, Oregon, in August 2013, at age 89.