Actor in the wings with ABC containing current language (6)
I believe the answer is:
arabic
'language' is the definition.
(Arabic is a language)
'actor in the wings with abc containing current' is the wordplay.
'actor in the wings' becomes 'ar' (I can't explain this - if you can you should give a lot more credence to this answer).
'with' says to put letters next to each other.
'containing' is an insertion indicator.
'current' becomes 'I' (symbol for electric current).
'abc' placed around 'i' is 'abic'.
'ar'+'abic'='ARABIC'
Can you help me to learn more?
(Other definitions for arabic that I've seen before include "Final" , "Language (by gum!)" , "foreign language" , "Language of North Africa and the Middle East" , "1 [GCSE]" .)