Source : Webster's Revised Unabridged Dictionary (1913)

Localism \Lo"cal*ism\, n.
   1. The state or quality of being local; affection for a
      particular place.

   2. A method of speaking or acting peculiar to a certain
      district; a local idiom or phrase.

Source : WordNet®

localism
     n 1: a phrase or pronunciation that is peculiar to a particular
          locality
     2: a partiality for some particular place [syn: {sectionalism},
         {provincialism}]