endonym

In preference of exonyms

Other difficulties with endonyms have to do with pronunciation, spelling, and word category. The endonym may include sounds and spellings that are highly unfamiliar to speakers of other languages, making appropriate usage difficult if not impossible for an outsider. Over the years, the endonym may have undergone phonetic changes, either in the original language or the borrowing language, thus changing an endonym into an exonym, as in the case of Paris, where the s was formerly pronounced in French. Another example is the endonym for the German city of Cologne, where the Latin original of Colonia has evolved into Köln in German, while the Italian and Spanish exonym Colonia or the Portuguese exonym Colónia closely reflect the Latin original.