Iu.
The sound of iu is either made up of the sound of both the vowels, or like u alone.
1. Made up of (1) i and (1) u: i short, u long, as, fiù worthy; u short, as, iuchair a key.
After a Lingual or a Palatal, not quiescent, the i loses its sound, and only qualifies that of the preceding consonant; hence,
2. Like (1) u: long, as, diù worst part, refuse; short, as, tiugh thick, giuthas fir.