Fall in pitch originally concerning gulf church (7)
I believe the answer is:
cadence
'fall in pitch' is the definition.
'cadence' can be an answer for 'fall' (I have seen 'Fall of pitch' mean 'cadence' so perhaps 'fall' could also mean 'cadence'). I am unsure of the 'in pitch' bit.
'originally concerning gulf church' is the wordplay.
'originally' indicates taking the first letters.
'gulf' becomes 'aden' (Gulf of Aden).
'church' becomes 'CE' (Church of England).
The first letter of 'concerning' is 'c'.
'c'+'aden'+'ce'='CADENCE'
Can you help me to learn more?
(Other definitions for cadence that I've seen before include "Lilt" , "Vocal modulation or inflection" , "Rhythm of the voice" , "Modulation of the voice" , "Close of a musical phrase" .)