One studying Shakespearian king and northern queen (7)
I believe the answer is:
learner
'one studying shakespearian' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'king and northern queen' is the wordplay.
'king' becomes 'lear' (King Lear).
'and' is a charade indicator (letters next to each other).
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'lear'+'n'+'er'='LEARNER'
Can you help me to learn more?
(Other definitions for learner that I've seen before include "neophyte" , "A student or beginner" , "He displays the L-plate" , "Acquirer of knowledge" , "Student (of driving?)" .)