Unlike Islamic missionary groups that focus on education as a means of conversion, the Wahubiri wa Kislamu (Preachers of Islam) specialize in giving sermons and preaching on the streets, at markets, or in football stadiums. They refer to these activities as "open-air conferences." Their sermons consist of an "Islamic" reading of the Bible, with the intention of converting Christians to Islam; hence their somewhat hybrid name. This article traces the emergence of this missionary method in East Africa. Regardless of how negatively the Preachers of Islam interpret the Bible, the fact that they do this in front of a mixed Muslim-Christian public could be interpreted as a contribution to greater mutual understanding between the groups. The Preachers of Islam exclusively use Swahili in their sermons and even render Quranic verses in Swahili. Analysis of the role of the vernacular (in relation to Arabic), in both Islam and Christianity, addresses the concept of the "translatability of the (religious) message" developed by Lamine Sanneh (Sanneh 1993).