Aerodynamic voicing constraint in stops: From Wolfgang von Kempelen to John Ohala

: Voicing in stop consonants is restricted by aerodynamical constraints, as illustrated by John Ohala, among others, more than three decades ago. It seems to be unnoticed in modern phonetic research that Wolfgang von Kempelen already described these challenges two centuries earlier. With additional bellows in his speaking machine he offered a mechanical solution for the vocal tract enlargement in stop production to achieve a longer voiced phase. A look back can help to develop a better understanding of the main mechanism for contrasting stops in many languages.