Source : Webster's Revised Unabridged Dictionary (1913)

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.

Phthongal \Phthon"gal\, n.
   A vocalized element or letter.