Stable condition without English in command (6)
I believe the answer is:
static
'stable' is the definition.
(I know that stable can be written as static)
'condition without english in command' is the wordplay.
'condition' becomes 'state' (I've seen this before).
'without' is a deletion indicator.
'english' becomes 'e' (abbreviation).
'in command' becomes 'ic' (military abbreviation).
'state' with 'e' taken out is 'stat'.
'stat'+'ic'='STATIC'
(Other definitions for static that I've seen before include "Not moving or changing" , "Not active, immobile" , "Still, not moving" , "Changeless" , "Still - radio interference" .)