They have something to say on the radio (8)

I believe the answer is:

speakers

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'they have something' is the definition.
The definition suggests an adverb but the answer is not.

'say on the radio' is the wordplay.
'say' becomes 'speak' (synonyms).
'on the radio' becomes 'ers' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'speak'+'ers'='SPEAKERS'

'to' is the link.

Can you help me to learn more?

I've seen this clue in The Globe and Mail.

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