I found a nice site on the net.  The human voice is the ultimate
musical instrument.  So there have been people (maybe because they did
not sing very well :->) who tried to build a speaking machine.  Not a
mechanical one, it's true.  The WWW-address is

   http://www.ling.su.se/staff/hartmut/kempln.htm


 [ Von Kempelen's machine is obviously an indirect ancestor of
 [ the modern phonograph/graphophone developed by Edison and
 [ Berliner and others, only 200 years earlier!  -- Robbie

 - - -

Wolfgang von Kempelen's speaking machine

The first attempts to produce human speech by machine were made in the
2nd half of the 18th century.  Ch. T. Kratzenstein, professor of
physiology in Halle and Copenhagen, succeeded in producing vowels using
resonance tubes excited by a vibrating reed (1773).

At that time, Wolfgang von Kempelen had already begun with his own
attempts in constructing a speaking machine.  Von Kempelen was a genius
in the service of Maria Theresia in Vienna.  He was born in 1734 in
Bratislava, then capital of Hungary, and he died in Vienna in 1804.
While he became known for various additional feats, his main concern
was the study of human speech production, with therapeutic applications
in mind.  He has been called the first experimental phonetician.

In his book, "Mechanismus der menschlichen Sprache nebst Beschreibung
einer sprechenden Maschine" (1791), he included a detailed description
of his speaking machine - in order for others to reconstruct it and
make it more perfect.  The six drawings (three plus three) shown here
below to the right, are taken from this book.  (Click on them for an
enlarged view, and use the back-button of your browser to return.)

Von Kempelen's machine was the first that allowed to produce not only
some speech sounds, but also whole words and short sentences.
According to von Kempelen, it is possible to acquire an admirable
facility in playing the machine within three weeks, especially if one
chooses the Latin, French, or Italian language, since German is much
more difficult because of its many closed syllables and consonant
clusters.

The machine consisted of a bellows that simulated the lungs and was to
be operated with the right forearm (uppermost drawing).  A
counterweight provided for inhalation.  The middle and lower drawings
show the 'wind box' that was provided with some levers to be actuated
with the fingers of the right hand, the 'mouth', made of rubber, and
the 'nose' of the machine.  The two nostrils had to be covered with two
fingers unless a nasal was to be produced.  The whole speech production
mechanism was enclosed in a box with holes for the hands and additional
holes in its cover.

The air flow was conducted into the mouth not only by way of an
oscillating reed, but also through a narrow shunting tube.  This
allowed the air pressure in the mouth cavity to increase when its
opening was covered tightly in order to produce unvoiced speech sounds.
Driven by a spring, a small auxiliary bellows would then deliver an
extra puff of air at the release.

With the left hand, it was also possible to control the resonance
properties of the mouth by varied covering of its opening.  In this
way, some vowels and consonants could be simulated in sufficient
approximation.  This was not really a simulation of natural
articulation, since the shape of the mouth of the machine in itself
remained constant.  Some vowels and, especially, the consonants [d t g
k] could not be simulated in this way, but only feigned, at best.  An
[l] could be produced by putting the thumb into the mouth.

The function of the vocal cords was simulated by a slamming reed made
of ivory (leftmost drawing).  Although the effective length of the reed
could be varied, this could not be done during speech production, so
that the machine spoke on a monotone.

Two of the levers to be actuated with the right hand served the
production of the fricatives [s] and [ ] as well as [z] and [] by means
of separate, hissing whistles (right drawing).  A third one effectuated
the production of a rattling [R] by dropping a wire on the vibrating
reed (middle drawing).

The final version of von Kempelen's machine is preserved to this day.
It was kept at the k. k. Konservatorium fuer Musik in Vienna until 1906,
when it was donated to the Deutsches Museum (von Meisterwerken der
Naturwissenschaft und Technik) in Munich, that had been founded three
years before.  There, it is exhibited in the department of musical
instruments.  This machine differs from the one described in the book
in the presence of a handle, to be operated with the palm of the right
hand, by which the oscillating length of the reed can be controlled
during speech production.  In this way it can be tried to simulate a
natural course of intonation.

A reconstruction of the machine, demonstrated by Wheatstone (1835) in
Dublin, differed from the version described in the book by having a
flexible oral cavity and active voicing control, but it lacked the
pitch control mechanism included in Kempelen's final version.

On July 8th, 1997, I enjoyed the privilege of being allowed to play von
Kempelen's machine.  Its voice production mechanism, including the
pitch control, was still functional.  The voice sounded like that of a
child or of an adult speaking quite loudly.

As soon as available, samples of speech produced with Wolfgang von
Kempelen's speaking machine (or a reconstruction of it) will be
presented here.

References: Wolfgang von Kempelen, Mechanismus der menschlichen Sprache
nebst Beschreibung einer sprechenden Maschine, Wien: J.V. Degen, 1791,
also published in French.

Le Mechanisme de la parole, suivi de la description d'une machine
parlante.  There is a reprint of the German edition, with an
introduction by H. E. Brekle and W. Wildgren, Stuttgart:
Frommann-Holzboog, 1970.

There are also more recent translations into Hungarian and Slovak.

 - - -

  The further history of speech synthesis (in German)
  Wolfgang von Kempelen on the Web
  Hartmut Traunmueller
  Inst. foer lingvistik
  Stockholms Universitet
  August 1997.