Chap challenging endless Chinese speech (8)
I believe the answer is:
mandarin
'endless chinese speech' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe there's an association between them I don't understand?
'chap challenging' is the wordplay.
'chap' becomes 'man' (chap can mean a man).
'challenging' becomes 'darin' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'man'+'darin'='MANDARIN'
Can you help me to learn more?
(Other definitions for mandarin that I've seen before include "Small orange-like fruit (from China?)" , "Asiatic duck" , "Language formerly used by educated Chinese, or a kind of orange" , "A billion people understand it" , "High-ranking public official" .)