French writer's pseudonym (3,2,5)
I believe the answer is:
nom de plume
This might be a double definition.
'french' is the first definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'writer's pseudonym' is the second definition.
(I've seen this in another clue)
Can you help me to learn more?
(Other definitions for nom de plume that I've seen before include "Soubriquet" , "Pen name" , "George Sand?" , "Author's pseudonym" , "Assumed name" .)