Vowels mary, merry and marry

Many speakers in eastern MA and northern NH have three distinct pre-rhotic front vowels, differentiated in the triplet Mary [e:] ~ merry [ε] ~ marry [æ], while those in VT and southern NH pronounce the three words alike (Nagy 2001; Nagy and Roberts 1998). Miller (1989: 99) reports that most speakers in Calais, ME, have a two-way merger: for 80% of the speakers, Mary and marry are [meri] and merry is [mεri]. 13% of the speakers surveyed have merged all three. (7% have slightly different two-way mergers.) This indicates a marked change from LANE, where a three-way distinction was maintained across NE (Miller 1989: 100).