Sons watch Bill (7)

I believe the answer is:

sticker

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'bill' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe there's a link between them I don't understand?

'sons watch' is the wordplay.
'sons' becomes 's'.
'watch' becomes 'ticker' (synonyms).
's'+'ticker'='STICKER'

Can you help me to learn more?

(Other definitions for sticker that I've seen before include "problem" , "Person with staying power" , "Adhesive label" , "Determined person" , "Gummed label" .)

I've seen this clue in The Sun.

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