When a common word from another language is borrowed into English, it tends to take on a more specific meaning. Most native English speakers wouldn't use "salsa" to describe any other sauce. Horno oven sounds perfectly reasonable in English to specifically describe an earth oven in that style, not the common household appliance.
EDIT: Probably the reason this happens is that most English speakers wouldn't be familiar with the foreign word, so the speaker uses it as a modifier to the standard English word. The listener doesn't need to know anything specific about the foreign word in that case and can just assume it's a type of the common item.
EDIT: Probably the reason this happens is that most English speakers wouldn't be familiar with the foreign word, so the speaker uses it as a modifier to the standard English word. The listener doesn't need to know anything specific about the foreign word in that case and can just assume it's a type of the common item.