Silent movies are those lacking any synchronized sound, relying instead on cards and gestures. The silent movie era lasted until the late 1920s, wen the Audion amplifier tube and the Vitaphone system enabled synchronizing dialog with film.
The first "talkie" having synchronized recorded sound was The Jazz Singer in 1927, which was the beginning of the end of silent movies.
An estimated 70% of silent movies have been lost, according a September 2013 report by the United States Library of Congress.[1]