First International Workshop on the History of Speech Communication Research (HSCR 2015)

Dresden, Germany
September 4-5, 2015

Kempelen vs. Kratzenstein – Researchers on Speech Synthesis in Times of Change

Fabian Brackhane

Institut für Deutsche Sprache, Mannheim, Germany

One was a distinguished natural scientist and engineer, the other a selftaught scientist and vilified as a conman: Christian Gottlieb Kratzenstein (1723– 1795) and Wolfgang von Kempelen (1734–1804). Some of the former’s postulations on human physiology and articulation of speech proved wrong in later years. Most of the latter’s theories are considered applicable even today. The perhaps most contrasting approaches to speech synthesis during the 18th century are linked to their names. There are many essential differences between their approaches which show that these two researchers were not only representatives of different schools of thought, but also representatives of two different scientific eras. A speculative and philosophical approach on the one hand versus an empirical and logical approach on the other hand. Both Kratzenstein and Kempelen published books on their research. But while the “Tentamen” [1] of the physician Kratzenstein remains rather vague and imprecise in its descriptions of vowel production and synthesis, the “Mechanismus” [2] of the engineer Kempelen shows much more precision and correctness in almost every respect of human speech and language. The goal of this paper is to discuss the differences between these two contemporaneous researchers on speech synthesis and to compare their theories with present-days findings.


  1. Kratzenstein, Ch. G.: Tentamen resolvendi problema ab illustri Academia Imperiali scientiarum Petropolitana ad annum 1780 publice propositum. Petersburg. 1781
  2. Kempelen, W.: Wolfgangs von Kempelen k. k. wirklichen Hofraths Mechanismus der menschlichen Sprache nebst Beschreibung seiner sprechenden Maschine. Wien: Degen. 1791.

Full Paper

Bibliographic reference.  Brackhane, Fabian (2015): "Kempelen vs. Kratzenstein – researchers on speech synthesis in times of change", In HSCR-2015, 42-49.