Narrative has tiny roles getting cast (9)
I believe the answer is:
storyline
'narrative' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'tiny roles getting cast' is the wordplay.
'getting' means one lot of letters go next to another.
'cast' is an anagram indicator (letters are dispersed or cast around).
'tiny'+'roles'='tinyroles'
'tinyroles' with letters rearranged gives 'STORYLINE'.
'has' is the link.
Can you help me to learn more?
(Other definitions for storyline that I've seen before include "Plot of a novel, play or film" , "Novelly structure" .)