Definitively voluble performers perhaps run separate schedules out of line (3,7)
I believe the answer is:
rap artists
'definitively voluble performers' is the definition.
I can't tell whether this definition defines the answer.
'run separate schedules out of line' is the wordplay.
'run' becomes 'r' (cricket abbreviation).
'separate' becomes 'apart' (similar in meaning).
'schedules' becomes 'lists'.
'out of' indicates named letters should be taken away.
'line' becomes 'l' (used when specifying particular lines from a poem).
'lists' with 'l' taken away is 'ists'.
'r'+'apart'+'ists'='RAP ARTISTS'
'perhaps' acts as a link.
Can you help me to learn more?
(Another definition for rap artists that I've seen is " performers".)