It is fantastic how many languages are spoken in Ethiopia. There are more than 80 languages! The main languages are Amharic, Oromiffa, Tigrinya and Guraginya. During the previous government, everybody was forced to learn Amharic. Now, Amaharic is still the official language, together with English, but in the provinces the local language is being used.
Amharic and Tigrinya are written in a different alpahbet, an Abugida fidel. This is a phonetic set of alphabet, with each letter representing a sound. It is not so difficult to learn, what you see is what you say.
Like in many other African countries, language has ben a means of oppressing the people. It used to be forbidden to speak Oromiffa. A very likely reason is that the tribe of Oromo is fighting to gain independence.
There are many foreigners who have learned Amharic, a number of Italians were born in Ehiopia and brought up there. Others have studied it for the sake of working in Ethiopia. Of course, many people can speak English. But knowing the local language does bring you closer to the people. Then, there are the many families who adopt children from Ethiopia and want to preserve their cultural heritage.