One who chooses to be English reader (7)
I believe the answer is:
elector
'one who chooses to' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'english reader' is the wordplay.
'english' becomes 'e' (abbreviation).
'reader' becomes 'lector' (synonyms).
'e'+'lector'='ELECTOR'
'be' acts as a link.
Can you help me to learn more?
(Other definitions for elector that I've seen before include "One crossing" , "One eligible to vote" , "A prince of the Holy Roman Empire" , "Someone with the right to vote" , "One whom may vote" .)