A silent film is a film with no synchronized recorded sound, especially with no spoken dialogue. In silent films for entertainment the dialogue is transmitted through muted gestures, mime and title cards. The idea of combining motion pictures with recorded sound is nearly as old as film itself, but because of the technical challenges involved, synchronized dialogue was only made practical in the late 1920s with the perfection of the Audion amplifier tube and the introduction of the Vitaphone system.