You're absolutely right that the introduction of talkies was a huge negative for the deaf community.

Before 1927's The Jazz Singer, deaf people had fully equal access to the movies just like hearing people. Films were reported on in newspapers published by and for the deaf community, and popular as outings for deaf people. They appreciated the heavily physical/visual comedy of silent movies, which translated well to people used to sign language; what looks like exaggerated camp to modern audiences was clear communication to deaf silent film audiences.

But deaf people were not only consumers of Hollywood movies, they were prominent actors. Granville Redmond featured in a number of Charlie Chaplin movies, playing hearing characters (except in You'd Be Surprised, where he played a deaf character who signed). Emerson Romero also played hearing characters - this was standard at the time, no speaking was ever needed, so they could appear hearing. There was even a film in 1926 with an all-deaf cast, His Busy Hour, directed and produced by hearing people.

But within three years after The Jazz Singer, nearly all movies were talkies, and deaf people haven't had equal access to movies since, relying instead on captions and other accommodations rather than having the same access as hearing people. Instead of films, deaf people in the 1930s turned to deaf-run theater for entertainment; these touring groups eventually became the National Theater of the Deaf in the 1960s. A few had the option to still see "subtitled" movies; some deaf people spliced them in themselves, silent-film style, and these were also sometimes shared around the community. But Hollywood films were inaccessible to deaf people until 1981, when the first open-captioned movie (Amy) was released in theaters. Even through the end of the 20th century, though, open captioned movies were uncommon, and deaf people typically waited until VHS and DVD releases brought them movies with captions; essentially, Hollywood didn't pay much attention to deaf audiences for about 70 years, and deaf people were forced to find their own forms of accessibility and storytelling.

For further reading, the chief work on this is Hollywood Speaks: Deafness and the Film Entertainment Industry by John S. Schuchman. If you have JSTOR access, his article The Silent Film Era: Silent Films, NAD Films, and the Deaf Community’s Response is on similar subjects. (Schuchman is the top scholar on this subject.)

Thanks for asking the question - I don't get a lot in my area and I'm happy to share!