Al Jolson's famous line (as Jack Robin) "You ain't heard nothin' yet." was an ad-lib. The intention was that the film should only have synchronized music, not speech, but Jolson dropped in the line (which he used in his stage act) after the song "Dirty Hands, Dirty Face". The director wisely left it in.
Many documentaries and historians state that immediately after the release and success of The Jazz Singer that all of Hollywood switched to sound. This is not true for several reasons. First, there were two competing and incompatible sound systems. The Vitaphone process was cumbersome, relying on an electro-mechanical interface between the projector and the turntable. Fox's Fotofilm was a superior sound-on-film process that allowed for easier editing but required a costlier projector (the Vitaphone system would be quietly killed off by 1932). Secondly, either sound process nearly doubled the budget of a film. Thirdly, theater chains faced enormous conversion costs (MGM-parent company Loew's Inc. owned over 1,000 outlets, and took a deliberately slow wait-and-see attitude toward sound). The first feature film with all synchronous dialog was Lights of New York. Also, in the midst of the talkie-craze of 1928-30, studio bosses were faced with a limited amount of sound equipment and qualified sound technicians, causing them innumerable headaches over which productions to produce as talkies vs. silents. Also, silents were internationally marketable via cheap title card translations while talkies, prior to the advent of subtitles, usually required completely different foreign language versions to be produced simultaneously. Low budget producers of westerns along poverty row were especially impacted, with silents continuing in that market through the end of 1930. Many studios continued to produce both silent and sound versions of their films, including the classic All Quiet on the Western Front.
Warner Brothers quietly threw in the towel on the Vitaphone disk process in 1932. Not wanting to risk losing the disks, Warner Bros. had all of the Vitaphone sound for the film transferred to optical tracks on the side of the film itself in the 1930s.
Sam Warner, the Warner Brother, that was nicknamed the "Father of the Talkies", because he insisted that Al Jolson's ad-libbed speech be included in the movie, died on Wednesday, October 5th, 1927, just one day before the film debuted, to the remaining cast and crew, on Thursday, October 6th, 1927.
The movie's opening line and quote, "Wait a minute, wait a minute. You ain't heard nothing yet" was voted as the #71 movie quote by the American Film Institute (out of 100), and as #57 of "The 100 Greatest Movie Lines" by Premiere in 2007.
According to the dates of the letter/telegram shown and the title card preceding Jakie's return to New York, and allowing one day for travel, the Cantor's date of birth would have been on Saturday, August 9th, 1867 or Sunday, August 10th, 1867.
"Lux Radio Theater" broadcast a 60 minute radio adaptation of the movie on Monday, August 10th, 1936 with Al Jolson reprising his film role. They did a second one on Tuesday, June 2nd, 1947. 3,949 days, 564 weeks and 1 day differ between these two radio adaptation dates.
The theatrical date of release, was on Saturday, February 4th, 1928. But it was first shown to and shown seen by the Warner Brothers' cast and crew, of directors, producers, actors and actresses, on Thursday, October 6th, 1927. 121 days, (17 weeks & 2 days), differ between the movie's date of release and the date, it was first shown to and seen by the Warner Brothers' cast and crew, of directors, producers, actors and actresses, (cast and crew members)before public theaters were allowed to show this premiere.
The role of Al Jolson's mother was first offered to Slovenian actress Avgusta Danilova, but for some reason she refused it. If she had accepted the role, she would become the first Slovenian actress to appear in a Hollywood film.
The trivia item below may give away important plot points.
According to the insert shot of the Winter Garden Theatre program, the date of the performance that Al Jolson's character passes up to sing "Kol Nidre" (and the date of the Cantor's death), which was on Wednesday, September 14, 1927.