It’s heard in Kabul at posh parties (6)
I believe the answer is:
pashto
'it's heard in kabul' is the definition.
I can't tell whether this definition defines the answer.
'at posh parties' is the wordplay.
'parties' indicates anagramming the letters (the letters move or party around).
'at'+'posh'='atposh'
'atposh' with letters rearranged gives 'PASHTO'.
Can you help me to learn more?
(Other definitions for pashto that I've seen before include "hear this from Afghanistan" , "Afghan" , "Iranian language spoken in Afghanistan and Pakistan" , "language follows!" .)