For a Better Understanding of the Common Origin of Love and Sorrow

The Chinese words
For love and sorrow
Consist of the same sound "ai"

But love is pronounced
With a falling intonation
And sorrow is pronounced
With a high pitch
In a straight line

It's the same sound "ai"
With a common point of origin
In one case it falls
With the gentleness of a lover's sigh
Whereas in the other
It persists with lament
Like a high pitched whine