Lose moisture and fall silent (3,2)
I believe the answer is:
dry up
'fall silent' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for dry up that I've seen before include "Rude command to stop talking, or polish dishes after washing" , "Become waterless, or rude command to stop talking" , "Turn off gas" , "Forget one's lines - become unproductive" , "Shed moisture or stop talking" .)