Q. [ij], [uw] became [i], [u]; [ijV|uwV] > [iV|uV]
Just as [ji], [wu] became [i], [u], the semi-vowels, y, w vanished when they followed the vowels i, u respectively. Such combinations are relatively rare. They mainly arose:
- When spirants vocalized before y, w: Vʒj, Vʒw > Vij, Vuw (PE19/75-76).
- When intervocalic y diphthongized after long vowel: V̄jV > VijV (PE19/62).
- From ancient suffixes like the abstract noun/gerundal suffix ✶-(i)yē > Q. -ie (PE17/58; PE22/137) and the perfect suffix ✶-iyē > Q. -ie (PE18/086).
- ✶ndagwē > ndau̯we > nau̯we > Q. naue (PE19/94).
- ✶māya > mā̆iya > Q. maia (PE17/163; PE19/62).
- ✶sarniye > Q. sarnie (VT42/11).
Conceptual Development: Tolkien mentioned similar reductions of semi-vowels in the Qenyaqesta of the 1910s:
i̯, u̯ vanished after e/i o/u respectively in certain frequent cases ... i̯ vanishes after i- (iı̯i > ī) ... u̯ vanishes after ú (uu̯u > ú) (PE12/12).