Looking at the German production and reception context, this article argues for increased attention to part-talkies as a transitional phenomenon and hybrid medium in film history. Part-talkies are films that alternate between silent and sound film sequences, creating ‘changes in register’, ruptures and ambiguities, which point to the unevenness and duration of cinema’s conversion to sound. The article presents several types of part-talkies and other hybrid films from around 1930, giving reasons for their marginalization in film historiography and the need for a critical and non-judgmental examination of their cultural, economic, and aesthetic implications. As a look at contemporary reviews in German trade papers reveals, part-talkies were the subject of heterogeneous debates on film aesthetics, in which differing views on their artistic value clashed. Furthermore, an exemplary historical analysis of the German part-talkie Cyankali (Cyanide) (dir. Hans Tintner, 1930) shows how the film’s hybridity resulted from its production history and became the focus of contemporary censorship debates. A close reading of some of the film’s sound sequences brings to the fore the complex audiovisual methods operating in the film, especially at moments of transition.