Final answer:
Vaudeville was the most popular theatrical entertainment in the U.S. until the late 1920s, with melodramas also being widely favored. The Jazz Singer, released in 1927, marked the successful transition to talking motion pictures.
Step-by-step explanation:
The most popular theatrical entertainment in the United States until the advent of the talking film in the 1920s was vaudeville, which was a large stage variety show encompassing a mix of singing, dancing, comedy acts, live animals, and magic.
Vaudeville and melodramas provided theatre-going audiences with an array of entertainment options. Melodramas were characterized by exaggerated stories and clear moral distinctions, featuring villains, damsels in distress, and heroic men.
The first successful talking motion picture in 1927, which signalled the decline of silent films and live vaudeville dominance, was The Jazz Singer, featuring Al Jolson.