Complex sentence: Fourteen years later, he begins to direct the movie, Hell's Angels, however after the release of The Jazz Singer, the first partially talking film, Hughes becomes obsessed with shooting his film realistically, and decides to convert the movie to a sound film.
Split into simpler sentences: Fourteen years later, he begins to direct the movie "Hell's Angels". However, after the release of "The Jazz Singer", the first partially talking film, Hughes becomes obsessed with shooting his film realistically, and decides to convert the movie to a sound film.