DIPHTHONGS BEGINNING WITH U.
U, in the proper diphthongs, ua, ue, ui, uo, uy, has the sound of w or of oo feeble; as in persuade, query, quell, quiet, languid, quote, obloquy.
Ua, an improper diphthong, has the sound—1. Of middle a; as in guard, guardian. 2. Of close a; as in guarantee, piquant. 3. Of obscure e; as in victuals and its compounds or kindred. 4. Of open u; as in mantuamaker.
Ue, an improper diphthong, has the sound—1. Of open u; as in blue, ensue, ague. 2. Of close e; as in guest, guesser. 3. Of close u; as in leaguer. Ue final is sometimes silent; as in league, antique. Ui, an improper diphthong, has the sound—1. Of open i; as in guide, guile. 2. Of close i; as in conduit, circuit. 3. Of open u; as in juice, sluice, suit.
Uo can scarcely be called an improper diphthong, except, perhaps, after q in liquor, liquorice, liquorish, where uor is heard as ur.
Uy, an improper diphthong, has the sound—1. Of open y; as in buy, buyer. 2. Of feeble y, or of ee feeble; as in plaguy, roguy.