Answer the following question: I know that the answer to the question "What allowed the language to be a factor?" is in "In 1926, Universal opened a production unit in Germany, Deutsche Universal-Film AG, under the direction of Joe Pasternak. This unit produced three to four films per year until 1936, migrating to Hungary and then Austria in the face of Hitler's increasing domination of central Europe. With the advent of sound, these productions were made in the German language or, occasionally, Hungarian or Polish. In the U.S., Universal Pictures did not distribute any of this subsidiary's films, but at least some of them were exhibited through other, independent, foreign-language film distributors based in New York, without benefit of English subtitles. Nazi persecution and a change in ownership for the parent Universal Pictures organization resulted in the dissolution of this subsidiary.". Can you tell me what it is?
Answer:
the advent of sound