Favored by government officials, diplomats, and explorers, protocol droids possess advanced language and social programming for facilitate conversations between varying species and cultures. Their advanced verbobrains allow them to speak millions of documented languages fluently, and even interpret new languages they have never heard before, based on known syntaxes and grammars. Because high-status individuals often use them, protocol droids are generally manufactured with sleeker, more highly polished exterior plating than most other droid models.

~ Source: Star Wars: The Old Republic Encyclopedia

AR-G0 (Taris)Pat-aK (Coruscant)BZ-9D (Tatooine)