This map superimposes all of the Southern isoglosses that have been presented so far. Three of these isoglosses isolate the most advanced representatives of the Southern dialects: speakers with more than 50% glide deletion of /ay/ before voiceless consonants, those with more than 50% back upglides with /oh/, and those with a relative reversal of /i/ ~ /iy/ as well as /e/ ~ /ey/.