Wikipedia: Swahili serves as a national, or official language, of four nations: Tanzania, Kenya, Uganda, and the Democratic Republic of the Congo. Some Swahili vocabulary is derived from Arabic through more than twelve centuries of contact with Arabic-speaking inhabitants of the coast of southeastern Africa. It has also incorporated Persian, German, Portuguese, English, and French words into its vocabulary through contact during the past five centuries.
Swahili is not really a combination of any number of languages. The language is basically of Bantu (African) origin, but it has borrowed words from other languages like Arabic among other African languages. See www.glcom.com/hassan/swahili_history.html for details.