User blog comment:Lordgeorge16/City-and-kingdom-based accents and languages in RuneScape Roleplay/@comment-25345260-20130424015330

Simple. Burthorpians before the update spoke random latin phrases. Zarosian is also Latin. But, the Zarosian lore is newer, so I'd say to go with that, and replace Burthorpe with Italian.

Sicarius, being a non-cannon group, do not have priority with accents.