Language
Zanzibarians speak Swahili (Kiswahili), a bantu language that is extensively spoken in the African Great Lakes region. Swahili is the official language of Tanzania. Many local residents also speak English and Arabic. There are local guides who can speak one of the occidental languages like French, Italian, Spanish, German and Portuguese.
Stop and say Hi! Swahili is an easy language to pick up, and the initial learning curve is quick. Learning just the basics will take you pretty far. Don’t assume the constant street side attention from people is an attempt to sell you something, or trap you into taking some sort of tour—that does happen, but saying hello is also an important part of the local culture. The “Mambos” and “Jambos” are often just that, so it’s a good idea to say hello back. It might be initially overwhelming, but it’s nice to realize that so many strangers will take the time to acknowledge your presence and ask you about your day. (A “Shikamoo”, usually reserved for those you don’t know, your elders or superiors, is a respectful greeting that locals will appreciate.)
Another thing, time-keeping is initially confusing, but actually makes a lot of sense. In Swahili culture, people start counting time at sunrise rather than at midnight, which means that 7 a.m. Western time is one o’clock in the morning Swahili time, and 7 p.m. is one o’clock at night. (This works because sunset and sunrise times are relatively constant year-round, since Zanzibar is so close to the equator.) A trick to decipher this code is to imagine drawing a line directly across a clock face: three becomes nine, four becomes ten. When arranging meeting times, it’s best to specify the time of day you’d like to meet—morning, afternoon, evening, night—that way, even if your numbers are off, chances are you’ll still be connect.