The boring sound of us makes one laugh (6)
I believe the answer is:
humour
'one laugh' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'the boring sound of us' is the wordplay.
'the boring sound' becomes 'hum' (hum is a kind of sound. I am not sure about the 'boring' bit.).
'of us' becomes 'our' (our means belonging to us).
'hum'+'our'='HUMOUR'
'makes' is the link.
Can you help me to learn more?
(Other definitions for humour that I've seen before include "Temperament; comedy" , "Sense of the comic?" , "Mood or something funny" , "A sense of . . . . . . - the quality of enjoying amusing things" , "Bodily fluid" .)