The Collaborative International Dictionary of English v.0.48:

Phthongal \Phthon"gal\, a. [Gr. ? voice.]
   Formed into, or characterized by, voice; vocalized; -- said
   of all the vowels and the semivowels, also of the vocal or
   sonant consonants g, d, b, l, r, v, z, etc.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Phthongal \Phthon"gal\, n.
   A vocalized element or letter.
   [1913 Webster]