It's both Italian, dear, and Latin for "song" (5)
I believe the answer is:
carol
'for song' is the definition.
(carol is a kind of song)
'it's both italian dear and latin' is the wordplay.
I cannot really see how this works, but
'latin' could be 'l' and 'l' is found in the answer.
'italian dear' could be 'caro' (I've seen this in another clue) and 'caro' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for carol that I've seen before include "Religious song - girl's name" , "Joyful song - girl's name" , "See 1" , "and 27: Waits" , "Female" .)