Ethiopian Ethnic Ethiopia's population is highly diverse, with over 80 different ethnic groups. The ethnic group has different cultural traditions and speaks a language that is unique to its race. In total, 87 indigenous languages are spoken in Ethiopia. And Amharic is the only official language. By: Rediet Shiferahu Oromo In Ethiopia Oromo, people are the largest ethnic group in Ethiopia. The Oromo language is known as Afaan Oromo. Among Oromo, there are three primary religions: the traditional Oromo religion, Waaqqefeta, Christianity, and Islam. Most Oromo people are followers of Islam and Christianity, while the remaining few follow the traditional Oromo religion. Holiday Oromo celebrate Irreecha to Thank Waaqa (God) for the blessings and mercies they have received in the previous year, the Oromo people celebrate Irreecha. At the beginning of spring, to welcomes the new season of abundant harvests associated with nature and creatures after the dark and rainy winter season.