Church has spoken of using voices (6)
I believe the answer is:
choral
'of using voices' is the definition.
The definition suggests a singular noun which matches the answer.
'church has spoken' is the wordplay.
'church' becomes 'ch' (abbreviation on maps etc).
'has' says to put letters next to each other.
'spoken' becomes 'oral' (similar in meaning).
'ch'+'oral'='CHORAL'
Can you help me to learn more?
(Other definitions for choral that I've seen before include "harmonious society" , "Sung by a choir" , "Sung psalm" , "Pertaining to a group of singers" , "19's 9th 16" .)