How the speaker communicates an appeal for a reunion! (6)
I believe the answer is:
orally
'how the speaker communicates an' is the definition.
I can't tell whether this defines the answer.
'appeal for a reunion' is the wordplay.
'appeal' becomes 'o'.
'for' is a charade indicator (letters next to each other).
'a reunion' becomes 'rally' (I can't explain this - if you can you should give a lot more credence to this answer).
'o'+'rally'='ORALLY'
Can you help me to learn more?
(Other definitions for orally that I've seen before include "By spoken word" , "as auditions are done" , "given by mouth" , "By (word of) mouth" , "given drugs thus?" .)