Telsur studies the merger of /i/ and /e/ before nasals most directly
pairs pin and pen, him and hem. This well-known Southern feature is
displayed in Map 3, with an isogloss showing the northern limits of those
communities that are solidly merged in production and perception.
In this map, the label "Merged in production & perception" applies
those subjects who reported both pairs to be 'the same' and whose
productions were judged the same by the analyst. The label "Distinct in
production & perception" applies to subjects whose productions were clearly
different to the analyst, but who reported them different or close. All
others fall into the "variable" class.
Brown 1990 shows that this merger was not complete in the South even
fairly recent times. But in Map 3, we see very little variation throughout
the Southern States in general. The area of consistent merger includes
Southern Virginia, most of the South Midland, and extends westward to
include all of Texas. The only variable region in the Southeast appears in
the South Carolina-Georgia area which is a distinct dialect region in many
other ways. A scattering of subjects with a clear distinction are found in
the western portion of the South Midland. Southern Florida is clearly
outside of this area.
The Northern limit of the merged area shows a number of irregular curves.
Central and southern Indiana is dominated by the merger, but there is very
little evidence of it in Ohio, and northern Kentucky shows a solid area of
distinction around Louisville.
In the west, there is a fair representation of merged speakers through
Denver, Nebraska extending up to Montana, in line with the settlement
history of this area. But the most striking concentration of merged speakers
in the West is in the Modesto valley of California, a pattern that may
reflect the trajectory of migrant workers from the Ozarks westward.
Brown, Vivian. 1990. The social and linguistic history of a
merger: /i/ and /e/ before nasals in Southern American English.
Texas A & M University dissertation.