triphthongal

• a word derived from triphthong.
  triphthong

  noun

  a monosyllabic speech-sound sequence perceived as being made up of three differing vowel qualities, as the pronunciation of our, especially in r-dropping dialects.

More Suggestions

• diphthong
• diphthongia
• tripersonal
• diphthongize
• tripodal
• triple-tongue
• triple integral
• chthonian
• diphtheria