Give a sermon at opening of Scientology summit (5)

I believe the answer is:

speak

I'm a little stuck... Click here to teach me more about this clue!

'give a sermon at opening of scientology summit' is the definition.
I can't judge whether this defines the answer.

'opening of scientology summit' is the wordplay.
'opening of' suggests taking the first letters.
'summit' becomes 'peak' (mountain peak).
The first letter of 'scientology' is 's'.
's'+'peak'='SPEAK'

Can you help me to learn more?

(Other definitions for speak that I've seen before include "give a lecture" , "Talk" , "express" , "Utter words" , "Orate" .)

I've seen this clue in the Sydney Morning Herald.

Want a hint initially instead of a full solution? Install my app