In many East African languages, the start of the daily time system is at dawn, not midnight. Thus, what would be seven o'clock in the morning in English becomes one o'clock in the morning in Swahili and other East African languages. This also affects the date: the whole night is the same date as the preceding day. For example, Tuesday does not become Wednesday until morning breaks, rather than changing at midnight.

For multi-lingual speakers in East Africa, the convention is to use the time system applicable to the language one happens to be speaking at the time. A person speaking of an early morning event in English would report that it happened at eight o'clock. However, in repeating the same facts in Swahili, one would state that the events occurred at saa mbili ('two hours').

The Ganda form, ssawa bbiri, is equivalent to the Swahili in that it means literally 'two hours'.