The front vowels transcribed as e = [e], and ae = or were originally diphthongs, as shown by the complex Hangul symbols reflected in the ey and ay of the Yale romanization.
The vowel ae is no longer kept distinct from e in southern Korea and the distinction is virtually lost in modern Seoul, though it is maintained in the spellings.
Classical pronunciation also used some diphthongs pronounced by educated Romans much as they are spelled, especially ae (earlier ai), pronounced perhaps as an open ē in rustic speech, au (rustic open ō), and oe (earlier oi, Late Latin ē).
This truth fand honest Tam o' Shanter, As he frae Ayr ae night did canter, (Auld Ayr, wham ne'er a town surpasses For honest men and bonie lasses).
But Tam kend what was what fu' brawlie: There was ae winsome wench and waulie, That night enlisted in the core, Lang after ken'd on Carrick shore; (For mony a beast to dead she shot, And perish'd mony a bonie boat, And shook baith meikle corn and bear, And kept the country-side in fear).
Thir breeks o' mine, my only pair, That ance were plush, o' gude blue hair, I wad hae gi'en them off my hurdies, For ae blink o' the bonie burdies!
