What was the first feature length film with a synchronized speaking sound track?

Released on October 6, 1927, "The Jazz Singer" was the first feature length movie to boast both a synchronized music sound track and a vocal sound track as well. This was not the first time a spoken soundtrack was presented in a movie however it was the first feature length production to offer this novel experience. Previous "talkies" as they were known, had been released but they were only short productions. While the "Jazz Singer" is considered the premier feature length movie with a synchronized sound track, only about 25% of the movie actually offered this new technology. Other parts of the movie were the songs sung by the actors as they provided lip synching to the musical soundtracks being played. Much of the on screen action was still dialogue free and accompanied by a musical score. The first movie to provide an entirely synchronized dialogue would not be released for 9 more months. But the "Jazz Singer" successfully marked the beginning of a new era in movies, beginning the death knell for the era of the silent movie.