Diphthongs are single syllables and therefore consist of a single impulse of breath. Diphthongs are defined as glides, that is, a quick transition between two vowels.
All English diphthongs are falling, since the first element is always more prominent than the second.
Diphthongs can be divided in closing and centring diphthongs.
Glides to I:
glides to U
glides to ə
eiə LAYER PLAYER
auə FLOwER SHOwER