Speech sound generation was mechanically modeled as early as the 18th century

Evidence

As early as at the end of the 18th century, it was shown experimentally by Christian Kratzenstein and Wolfgang von Kempelen that the generation of speech sounds can be explained using an acoustic–mechanic model (Flanagan, 1972; Schroeder, 1993). — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 546

Categorization

• CANDY: A fun historical nugget: speech synthesis by acoustic-mechanical models predates electronics by 150 years — great elevator trivia.
• XREF: Connects to von Kempelen’s speaking machine, which later inspired other synthetic voice projects in the acoustic communication literature.
• corroborated: 2 independent passages support this claim — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 546