The commune of Buyenzi ( Wilaya ya Buyenzi, in Swahili) is a historic commune (District) of Bujumbura Mairie Province in western Burundi. The district is known for its Swahili heritage and influence not just in Bujumbura but Burundi as a whole. Buyenzi communie is laid on a grid plan and has 25 horizontal numbered streets.

Following the 1830s, commercial relations between the Lake Tanganyika region and the Swahili traders of the Indian Ocean grew more intense, and Ujiji, located at the western end of one of the main overland caravan routes, quickly gained significance. Through ordinary daily interactions between traders and the local populace, Lake Tanganyika gradually developed into a "second Swahili coast," adopting many of the distinctive Swahili traits, such as the Swahili language, Islamic architecture and attire, and Islam itself.

As the first Swahili settlement for the specific neighborhood, Buyenzi is home to the majority of Burundian Muslims who are mostly descendants of Swahili merchants from the Swahili Coast in the early 19th Century. Masjid Al Jummaa of Buyenzi, located on 12th and 13th streets of Buyenzi, is the second-largest mosque in Burundi and reflects the Swahili Islamic heritage.

Due to caravan trade networks from the East African coast into the interior, the Swahili language had historically been spoken around the beaches of Lake Tanganyika since the second half of the 19th century. The German colonial authorities, who encouraged the spread of Kiswahili in Tanganyika, the hub of German East Africa, particularly in the early 20th century, instrumentalized the language as a counterforce against the spread of English, however, were responsible for the language's initial widespread introduction.

When examining a dispute that occurred in 1902 at the Reichskolonialamt, it also becomes clear that Kiswahili was widely used and taught in the German colony (such as in the German school in Gitega). The disagreement was about funding for a Kirundi dictionary, which was suggested by the Catholic missionary van der Burg but rejected by the German governor Graf von Götzen, who suggested Kiswahili instead because it was more widely spoken. Germans "became so enamored with Kiswahili that they even imagined transplanting it to Cameroon" during the colonial era because it was perceived as a bulwark against English, the main colonial language.

Kiswahili was never widely adopted (or diffused) in Burundi as it was under the German occupation of Tanganyika. The first school in Usumbura (today's Bujumbura) was established in 1909 by the German Residentur, who chose Kiswahili as the medium of teaching because it was the only official language in Ruanda-Urundi. The result was that, "the Swahili language, supplemented by the defining characteristics of the Swahili culture, was instituted in Bujumbura and all its inhabitants spoke the language as a lingua franca".

Kiswahili has continued to be used in Bujumbura, but its standing and renown have altered throughout time. According to Belt, who emphasizes that initially it used to be the language that united people from different backgrounds but later changed into the language of strangers, Muslims, and "uncivilized" people, the language was not only spoken by various groups but also associated with various linguistic ideologies and inherent attitudes.

Belgium was handed the mandate over Ruanda-Urundi after the First World War, when Germany was defeated. The main reason they first upheld the German linguistic policy was that Swahili was also spoken in the Belgian Congo along the coast of Lake Tanganyika. It was unfathomable to be unable to communicate in Swahili, but throughout time, numerous new regulations came into effect, affecting Bujumbura's residents' social, economic, and linguistic circumstances significantly. Bujumbura grew more stratified as the Belgians attempted to create distinct economic and physical sectors for the various racial groups. Boundaries were also set within the town, just as they had been between rural and urban areas.