Are there any English dialects that fully distinguish singular and plural second-person pronoun?
Hiberno-English, which is the set of dialects natively written and spoken in Ireland, distinguishes between singular and plural second-person pronoun. Depending on the region, the plural pronoun can be "ye", "youse", or "yiz".
Mirroring Irish, and almost every other Indo European language, the plural you is also distinguished from the singular in Hiberno-English, normally by use of the otherwise archaic English word ye; the word yous (sometimes written as youse) also occurs, but primarily only in Dublin and across Ulster. In addition, in some areas in Leinster, north Connacht and parts of Ulster, the hybrid word ye-s, pronounced "yiz", may be used. The pronunciation differs with that of the northwestern and the Leinster pronunciation.