OMG I just thought to look up Somalia in Wikipedia and this is from the lead:
has been described as Africa's most culturally homogeneous country.
The sources:
What is more puzzling is how this could happen in a country like Somalia, the most homogeneous country in Africa both ethnically, religiously, culturally, and linguistically
Somalia, the only homogeneous country in Africa – all its people being ethnic Somalis speaking the same language and professing the same religion
OMG I just thought to look up Somalia in Wikipedia and this is from the lead:
The sources: