The polite form Sun 'Mister, Sir' is sometimes regarded as a pronoun. However, it can be used in a 3rd person context, and it is possible to use any proper noun or title in this function (san 'lady', arê 'king', Pedu 'Peter'). Thus, Principense is a language where title nouns and names can be used as second-person forms.
Source: Maurer 2009: 58