I'm sure you've noticed that the way people who have been raised in the Fall River area say certain words differs from the way they are pronounced by people who grew up in the New Bedford area.  

A couple of words that come to mind are "coffee", and "call."  In Fall River those words are pronounced very similar to the way you would hear them in the Brooklyn or Bronx areas of New York.  Of course this is a generalization and does not apply to everyone from the two cities.

Over the weekend I was given an explanation as to why this is.   A police officer in Fall River told me that the city was settled by people who had come to the area on steam boats from the New York City area to work in the textile mills.   The accents have been in many cases carried down through the generations. That is not the case with New Bedford where immigrants came more directly from Europe.   Many of those who came to the Whaling City did so for the fishing industry.

Sounds reasonable to me.   The big difference in the two cities is the fishing industry in New Bedford versus a more prominent textile industry that existed in Fall River.   Maybe the officer is not completely pcorrect, but I'm buying her explanation.