My pun does turn on an authorial tag (9)
I believe the answer is:
pseudonym
'an authorial tag' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'my pun does turn' is the wordplay.
'turn' is an anagram indicator.
'my'+'pun'+'does'='mypundoes'
'mypundoes' with letters rearranged gives 'PSEUDONYM'.
'on' acts as a link.
Can you help me to learn more?
(Other definitions for pseudonym that I've seen before include "Fictitious identity" , "Name adopted by someone for a particular role" , "Goliath, for one" , "Alias" , "Our cryptic crossword always carries one" .)