Leader of organisation helping to make speech (7)
I believe the answer is:
oration
'speech' is the definition.
(oration is a kind of speech)
'leader of organisation helping' is the wordplay.
'leader of' indicates taking the first letters.
'helping' becomes 'ration' (I've seen this before).
The initial letter of 'organisation' is 'o'.
'o'+'ration'='ORATION'
'to make' is the link.
(Other definitions for oration that I've seen before include "lecture" , "Power of speech" , "Making a speech" , "A formal or ceremonial speech" , "eulogy" .)