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Preface
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vocabulary was restricted, and the output speech quality required extensive learn-
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ing. At that time, the computer implementation used for research consisted of a
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Digital Equipment Corporation PDP-1 used for character recognition and morph
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analysis, which was coupled to MIT Lincoln Laboratory’s TX-O computer (the
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only one of its kind) for the synthesis algorithms. T. P. Barnwell III and
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E. R. Jensen were responsible for building much of this computational environ-
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ment. This required great effort and coordination, since all coding was performed
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in assembly language.
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Following the late 1960s, the character recognition and speech synthesis ef-
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forts continued independently of one another with the work of B. Blesser,
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M. Eden, and D. E. Troxel focused on the character recognition efforts. J. Allen
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joined the faculty in September, 1968. Goals for a fundamental and comprehen-
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sive research program aimed at the computation of high-quality speech using un-
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restricted English text as input were formulated. In addition, strong coupling con-
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tinued with the Speech Communication and Linguistics groups within the
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Research Laboratory of Electronics, led by K. N. Stevens and M. Halle, respec-
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tively.
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With the desire to convert unrestricted English text to speech, a new scheme
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was developed for the pronunciation of all possible English words. This required
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elaborate extensions to the morph decomposition process, as well as the construc-
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tion of a comprehensive morph lexicon to serve the entire language. Furthermore,
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spelled speech was rejected as inadequate, and plans for the development of a
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comprehensive set of letter-to-sound rules that would complement the morph
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analysis process were established. In order to build a new morph lexicon, a copy
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of the Brown corpus was obtained and sorted (shortest word first). Initial phonetic
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segment labels were obtained from a computer-readable copy of the Merriam
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Pocket Dictionary. Beginning with a nascent lexicon containing all bound morphs
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and function words, each word from the Brown corpus was successively analyzed.
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This led to the interactive addition of new morphs and a great deal of experience
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with morph analysis procedures. This process was accomplished by J. Allen and
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D. A. Finkel, with algorithmic and programming support from E. R. Jensen and
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F. X. Carroll. The process spanned many months, and led to the extension of
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morph analysis routines to include multiple decompositions and attendant selection
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rules. The computational support for this work was a Digital Equipment Corpora-
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tion PDP-9 computer with 24K words of memory and DEC tapes for peripheral
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storage. Readers familiar with this equipment will have some appreciation of the
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sheer magnitude of the effort required to build the morph lexicon and acquire the
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