Contributor to our duplicitous language (4)
I believe the answer is:
urdu
'language' is the definition.
(Urdu is an example)
'contributor to our duplicitous' is the wordplay.
'contributor to' indicates the answer is hidden within the clue (the letters of the answer contribute to the clue).
'URDU' is hidden in the letters of 'our duplicitous'.
(Other definitions for urdu that I've seen before include "Foreign language" , "Sanskrit language" , "Indian language" , "Analyse and develop (an idea) in detail" , "Language akin to Hindi" .)