Martin the Mess writes, on the subject of French-derived place names, “Here in Illinois, we infamously mispronounce most of our French-derived placenames, such as Versailles (Ver-SAYLES), Des Plaines (DESS-Playnes), and Cairo (KAY-Row). I know the last one there is technically not French, but we manage to blame them for our mangling of it nonetheless.”
There is a borough of Ver-SAYLES on the Youghiogheny just outside McKeesport, and it is likely that there are many others in the United States. But Dr. Boli does not regard “Ver-SAYLES” as a mispronunciation. Famous foreign places have English names—Rome (not Roma), Moscow (not Москва), Munich (not München), Athens (not Αθήνα or Ἀθῆναι), and so on. As we become more ignorant of foreign places, we lose those native English names for them one by one, and have to go back to the foreign names when we do want to talk about them.
One of the more recent losses is Marseilles, so spelled (and pronounced “Mar-SAYLES”) until well past the middle of the twentieth century. A Merriam-Webster Geographical Dictionary from 1966 gives “Marseilles” as the only recognized spelling in English, and “Mar-SAYLES” as the only recognized pronunciation. Now, of course, you will be either politely corrected or snobbishly derided if you use the English spelling and pronunciation.
The same thing happens with foreign personal names. Who recognizes the name “Tully” today? We must say “Marcus Tullius Cicero” if we are to be understood. Yet the use of the correct Latin form is not a sign of better education, but of darker ignorance. Tully had an English name because he was a subject of everyday conversation in English.
Thus we may take the persistence of an English name for a foreign place as an indication that English speakers can still imagine that place as actually existing and potentially worth talking about, whereas foreign places that have lost their English names are at best unsubstantiated geographical rumors.
Local traditions, however, are more stubborn, and the English pronunciations of many foreign names are preserved in places like Ver-SAYLES and CAY-ro. You will not be able to extinguish the persistent belief that those names are “pronounced wrong,” but fortunately you will not be able to extinguish the pronunciation, either.
There is still no excuse for DESS-Playnes.