Sound films were considered by so many to be a fad. They would last a while and then the industry would revert back to silent films with live music and effects. The studios wanted this – having to rebuild their studios to accommodate sound recording equipment was going to be expensive. Movie theatre owners did not want it either, again because of the expense.
Eventually, as we know, pre-recorded sound became a thing, forever.
It certainly had an effect on the industry. Musicians who had worked in cinemas were out of a job, or at least had to find new jobs. The soundtrack was on the film, or at least on discs synchronised with the film. The studio orchestra did all the playing that was necessary. Customers in any cinema around the world could hear the exact same musical score.
As far as actors and speech were concerned, many had to re-evaluate their futures. Some silent stars who had heavy accents either had to retire or move back to their country of origin.
Voice coaches were employed for many. Again, “Singin’ In The Rain” shows this a little. Some stars continued but ultimately failed. A key example is John Gilbert who had been a huge star iin silents but, when he moved into talkies, the gossip was he had a terrible voice. It’s not true at all, he has a fine voice, it was just an opportunity for studio bosses to plot his ruin.
And, of course, stars like Garbo who had a heavy Scandinavian accent flourished. Her accent just added to her exotic air of mystery.
And what of comedians? Harold Lloyd continued into the sound era and created many more good films. Buster Keaton tried, but it didn’t work. Laurel and Hardy had been big silent stars, and became even bigger stars in the sound era.
Charlie Chaplin resisted. Remember that Charlie Chaplin at some point was one of the most famous and recognisable people in the world (especially in his tramp, or “little fellow”) guise. In 1931, when Chaplin released his masterpiece “City Lights” as a silent film with title cards and recorded music, the fact that there was no ‘talking’ was seen as an old-fashioned, unpopular and an out-of-step move.