A vocabulator, also known as a vocoder or speech generator, was a device that synthesized a voice to allow droids to speak. They could also be used in helmets.
Utility droids typically had simple vocabulators, only capable of speaking binary, which consisted of beeps, hums, and whistles strung together into sentences. Others were fitted with more complex units that could mimic the language of almost any organic species. BX-series droid commandos were equipped with vocabulators that could be modulated to allow them to sound more like organic lifeforms, as a means of infiltration.
Translating vocoders could translate spoken words in real time. They were utilized by members of the New Republic Senate to translate their speech into Galactic Basic Standard.
Members of some species wore vocoder masks on a daily basis.
Kylo Ren's helmet included a built-in vocoder which modulated his voice. Phasma's armor also employed a vocoder.