Quietly stood up for plain English (5)
I believe the answer is:
prose
'plain english' is the definition.
(I've seen this in another clue)
'quietly stood up' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'stood up' becomes 'rose' (I've seen this in other clues).
'p'+'rose'='PROSE'
'for' is the link.
(Other definitions for prose that I've seen before include "Ordinary writing" , "Ordinary spoken or written language" , "Ropes (anag.)" , "Text" , "Non-verse" .)