A notedly low price (4)
I believe the answer is:
song
'price' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for song that I've seen before include "Lied" , "See 9" , "Tune" , "Vocal item" , "Piece of music, usually with words" .)