Question one -- capital of Zambia could be part of this (4)
I believe the answer is:
quiz
'part of this' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe there's an association between them I don't understand?
'question one capital of zambia' is the wordplay.
'question' becomes 'qu'.
'one' becomes 'i' (Roman numeral).
'capital of' says to take the initial letters.
The first letter of 'zambia' is 'z'.
'qu'+'i'+'z'='QUIZ'
'could be' acts as a link.
Can you help me to learn more?
(Other definitions for quiz that I've seen before include "Test consisting of short questions" , "Q-and-A entertainment" , "Panel game" , "Grill" , "Questionable entertainment?" .)