Part-talkie

A part-talkie is a partly, and most often primarily, silent film which includes one or more synchronous sound sequences with audible dialog or singing. During the silent portions lines of dialog are presented as "titles"—printed text briefly filling the screen—and the soundtrack is used only to supply musical accompaniment and sound effects. 
In the case of feature films made in the United States, nearly all such hybrid films date to the 1927–1929 period of transition from "silents" to full-fledged "talkies" with audible dialog throughout. It took about a year and a half for a transition period for American movie houses to move from almost all silent to almost all equipped for sound. In the interim period, studios reacted by improvising four solutions: fast remakes of recent productions, "goat gland" pictures with one or two sound sequences spliced into already finished productions, dual sound and silent versions produced simultaneously, and part-talkies.
The famous so-called "first talking picture", "The Jazz Singer" (1927), starring Al Jolson, is in fact a part-talkie. It features only about fifteen minutes of singing and talking, interspersed throughout the film, while the rest is a typical silent film with "titles" and only a recorded orchestral accompaniment.
History.
As the financial success of early part-talking feature-length sound films such as "The Jazz Singer" and "The Singing Fool" became apparent, producers of silent films which were currently in production, or which had recently been completed but not released, hastened to add or retrofit synchronized dialog sequences so that their films could be advertised as "talking pictures" to a newly sound-hungry public. "You will hear the characters speak from the screen!" the ads could truthfully promise, even if all the audible speech was confined to one brief sequence in an otherwise mute film.
However, some films were hurt rather than helped by such alterations.
The Paul Fejos film "Lonesome" (1928), an otherwise excellent late silent film, was injected with a gratuitous "talkie" sequence consisting of several minutes of banal small talk between the lead characters. This "goat gland", as such additions were sometimes called, succeeded mainly in causing previously sympathetic audiences to abruptly lower their opinions of the characters' personalities and level of intelligence.
In 1928, Universal Pictures began filming Edna Ferber's novel "Show Boat" as a silent film, but influenced by the success of the smash hit Broadway musical version, they halted the filming midway through production, added two sound sequences to the film, and made a sound prologue featuring three of the stage musical's actors singing five songs from the show. (The prologue was intended to be shown just before the actual film at every theatre wired for sound.) The film, prologue and all, was finally released in 1929. It was not a success. (The stage musical "Show Boat" was filmed in 1936 and 1951 with much better results, both critically and at the box office.)
The first film version of Thornton Wilder's "The Bridge of San Luis Rey", also released in 1929, had a few minutes of sound tacked onto what was basically a silent picture.
Douglas Fairbanks' last swashbuckler, "The Iron Mask" (1929) (based on Dumas's "L'homme au masque de fer"), featured a sound prologue, in which Fairbanks' speaking voice was heard from the screen for the first time, but the body of the film had no audible dialog.
In 1930, the Lon Chaney, Sr. silent film success "The Phantom of the Opera", originally released in 1925, was reissued with some newly filmed talking sequences added. It was not considered better than the silent version, although this reissue did make an additional million dollars. The film is now always shown silent, in which form it remains one of the great classics of the screen.
Unfortunately, the original negative of completed films was usually cut up in the process of creating part-talkies, permanently destroying the best quality copy of the original version. Many famous silent films, like "Lonesome", now only survive in their recut reissue versions. Others, like Charlie Chaplin's "The Gold Rush" (1925) and "The Phantom of the Opera", now only exist in good quality in their recut variants.
By late 1929, virtually all films in production in the US were "100 percent all talking", although there were rare but sometimes notable and successful exceptions. Charlie Chaplin's "Modern Times", released in 1936, is an example of an unusually late part-talkie. The only voices heard in the film are those of the factory foreman, of a salesman making his pitch by means of a phonograph record, and of Chaplin when he sings a gibberish song in a nightclub sequence. The soundtrack for the rest of the film is simply an orchestral score accompanying the action, with occasional sound effects.
The film "The Artist" (2011), winner of the 2012 Academy Award for Best Picture, was promoted as a silent film and the first of its kind to win a major Oscar award since the 1920s, but it was in fact a part-talkie due to the use of on-screen dialogue at the end, audible female laughter in a dream sequence, and the appearance of a song with sung lyrics on the soundtrack.