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.
Closing diphthongs:
Glides to I:
eI FADE
aI LIE
oI BOY
glides to U
əu KNOW
au DOWN
centring diphthongs:
glides to ə
iə BEER
eə BEAR
uə POOR
TRIPHTHONGS
eiə LAYER PLAYER
aiə FIRE
oiə LAWYER
əuə LOwER
auə FLOwER SHOwER