Conversation so far:
what was interesting about slavery and the oromo people?
While slaves were a stratum within the society, many Oromo people, regardless of caste, were sold into slavery elsewhere.
were Oromo people only classified as slaves because of language?
what was special about the Oromo slaves?
Oromo slaves were sought after and a major part of slaves sold at Ethiopia-Sudan border, as well as the Massawa and Tajura markets on the Red Sea.

Question: what other ethnic goups did they enslave?
Self-contained rewrite: what other ethnic goups were enslaved besides the Oromo people?