A bleat is the sound that a lamb makes.
A bleat.
the noise a lamb makes
the sound that a sheep makes is called 'bleeting"
You write sizzle.
ting
squeak
BOOM!
bacock
The sound a lamb makes is referred to as a "bleat".
You could write Bzzzz or Zzzz or any other buzzing sort of sound.
The sound a whistle makes is often described as "whoo" or "wee" depending on the pitch and intensity of the sound.