Place Name Learning Curves

Learning to pronounce place names is a challenge.  Growing up in Illlinois, we were always irritated with people who would say IllinoiS, pronouncing the S.  And then of course there was Cairo, IL which is pronounced Caro, as in the syprup. 

When I went to school in Missouri I had to learn to pronounce Nevada, Missouri as NevAda (long A), Missoura.  When I lived in England, I had to find out the hard way that Leicester was Lester.
In Louisiana, Natchitoches, Louisiana is Nakoditch, Loozeean.

In New Zealand it took me quite some time to figure out that Wh was an "f" sound in the Maori language and that typically each syllable had equal emphasis.  Whangarei was Fangarei with an equal emphasis on each syllable and almost as a growl.  I could not match what I was hearing and what I saw in text for the longest time. 

In China I struggled with matching text with sound as well.  It was only on my second tour of duty in Hong Kong that I began to put Chinese city names with the printed text.  I can now pronounce Xi'an and have a visual image of where it is on the map as well.

I am now living north of Boston.  I have been on a new learning curve.  I have learned that Gloucester is Glawster and better yet, Peadbody is Peebdy with the accent on the first syllable.  In fact it seems that everything is run together at the end.

All of this raises a challenging question for a geographer.  Do we use pronunciations as they "should" be, when speaking or writing outside a local context?  Or do we use local pronunciations in all situations?  When I teach geography or talk about the Appalachian Mountains, should I say Appalachuns (short A all the way through), or AppalAshuns?  What is "right"?

I am having an existential, geographical crisis.  I don't know if I live near Peabody or Peebdy.