the production of double vocal sounds.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
diphthongia(dif-thong′ē-ă, ′gē-ă, ′jē-ă, ′jă) [ diphthong + -ia]
The simultaneous utterance of two vocal sounds of different pitch in pathological conditions of the larynx.
Medical Dictionary, © 2009 Farlex and Partners