Vibration and no vibration
(Voiced and unvoiced)
When we speak we make some sounds with vibration in our voice box and some without vibration.
All vowels and many of the consonants are said with vibration in English.
Often the vibration is very small so you may not notice it.
To feel the difference, put your hand firmly on your voice box at the front of your throat and say:
ssssssssssssssss Do you feel the vibration?
zzzzzzzzzzzzzzzzzz Do you feel the vibration?
Here is a table of the consonants without vibration in English
and the corresponding consonants with vibration.
as in thank
as in the
as in she
as in pleasure
as in catch
as in edge
This will help you to understand the different pronunciations of the -ed verb endings.