Complex sentence: In the early years of sound films, Hollywood studios produced foreign-language versions of some of their films using the same sets and sometimes the same costumes, with native speakers of the language usually replacing some or all of the original cast.
Split into simpler sentences: In the early years of sound films, it was common for Hollywood studios to produce foreign-language versions of their films using the same sets and sometimes the same costumes. Native speakers of the language usually replaced some or all of the original cast.