Alternatively reach friend by word of mouth (6)
I believe the answer is:
orally
'by word of mouth' is the definition.
(I've seen this before)
'alternatively reach friend' is the wordplay.
I cannot really see how this works, but
'alternatively' could be 'or' and 'or' is present in the answer.
'friend' could be 'ally' (an ally is a friend or supporter) and 'ally' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for orally that I've seen before include "By spoken word" , "given by mouth" , "via the trap" , "By (word of) mouth" , "as auditions are done" .)