Mouth part starts to ululate vocals -- ukulele lead's awesome (5)
I believe the answer is:
uvula
'mouth part' is the definition.
'uvula' can be an answer for 'part' (uvula is a kind of part). I am not sure about the 'mouth' bit.
'starts to ululate vocals ukulele lead's awesome' is the wordplay.
'starts to' suggests taking the first letters.
The first letters of 'ululate vocals ukulele leads awesome' is 'UVULA'.
Can you help me to learn more?
(Other definitions for uvula that I've seen before include "Fleshy part of the palate" , "Fleshy lobe" , "Fleshy piece hanging over the throat" , "Fleshy body over back of tongue" , "Fleshy flap" .)