During the 1920s American films dominated the worldwide industry, but they were greatly influenced and enhanced by developments and personalities from Europe. The Russians Sergei Eisenstein ( Potemkin, 1925) and V. I. Pudovkin ( Mother, 1926) were especially influential in their understanding of montage (the relationship of the images to each other and the meaning that results). American interest in fantasy was influenced both directly and indirectly by The Cabinet of Dr. Caligari ( 1919) directed by the German Robert Wiene and Destiny ( 1921) directed by an Austrian working in Germany, Fritz Lang.
Some Europeans came to America to make films: Ernst Lubitsch, Victor Seastrom, and F. W. Murnau, for examples. The influence on American film of these films and filmmakers was profound; they left their strong impression on what came to be known as the Hollywood movie.
The story surrounding the coming of sound to movies is a complex and complicated one. The idea of connecting sound to the visuals was an old one; Edison had in fact entered the movie business because he was searching for visuals to go with the phonograph he was already marketing. To convert the movie technology to sound was expensive. Despite development of the necessary technology (most notably in this country by Lee de Forest), the industry was reluctant to invest in the change. In the mid-1920s Western Electric developed a method for putting the sound on a disk that could be roughly synchronized with the film. None of the big studios could be convinced to try it, but Warners Brothers was about to be forced out of business by the other, larger companies. It had little to lose and decided to take the risk. For a year Warners distributed a program with short sound films of slight interest, but on October 6, 1927, it premiered The Jazz Singer with Al Jolson. Sound was used to help tell the story, and the public loved it. Quickly, Warners established its financial base, and other studios rushed to emulate them; but problems developed. Studios had to reequip themselves. The camera, which had been struggling to free itself and discover new methods of expression, found itself confined to a large box and immobile. Actors had to learn to speak to their audiences, and exhibitors had to invest in sound projectors and speakers. Once the problems were overcome, however, the marriage of sound to the visuals became a natural extension of the art.