The King of the Kongo

The King of the Kongo 1929 is a Mascot film serial, and was the first serial to have sound, although only partial sound Part Talking rather than the later and obviously now standard AllTalking productions with complete sound.

The King of the Kongo was the first film serial to have any sound element. Larger serialproducing studios for example, Path and Universal Studios were reluctant to change away from silent production although Universal released their own PartTalking serial, Tarzan the Tiger, later in the same year while smaller studios could not afford to do so. Legend has it that producer and studioowner Nat Levine carried the sound discs in his lap from Los Angeles to New York City, by train and aeroplane, for them to be safely developed. For financial reasons, these discs could not have been repaired or replaced if anything had gone wrong. This was two years after the first PartTalking film, The Jazz Singer 1927, had been released and a year after the first AllTalking film, Lights of New York 1928.Despite an announcement that two versions of this serial would be released, a Part Talking version and a silent version intended for theatres not yet equipped for sound, no evidence for a silent version ever being released exists. Some of the video bootlegs of the film are the sound version with the sound credits excised. ........

Source: Wikipedia