digraph iV

i + {a, e, i, o, u}

ia: hiatus, diagram, Pryanka, dialect
ie: piece, tootsie, requiem (hiatus), lenient (hiatus)
io: hiatus'ed -ious, -ion,
iu: hiatus'ed -ium, triumph, diurnal

No iw, iy

Except for ie, all are hiatus'ed.