What was the first feature-length Hollywood talkie to use spoken dialogue as part of the dramatic action?

Answer 1

The Jazz Singer (1927)

Often misunderstood as the first sound movie, the first talkie, or the first movie musical, The Jazz Singer (1927) was actually only 25% talkie. It also had musical numbers and accompaniment that were sound-synchronized. The first sound movie is the silent Don Juan (1926), with a synchronized musical score and sound effects. The first talkie (all dialogue) feature-length movie is Lights of New York (1928) and the first musical is The Broadway Melody (1929).