Dove, perhaps, but not swallow (4,10)
I believe the answer is:
past participle
This clue might be a double definition.
'dove' is the first definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'but not swallow' is the second definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'perhaps' acts as a link.
Can you help me to learn more?
(Another definition for past participle that I've seen is " had, say".)