Zulu's close relative has ox to transport (5)
I believe the answer is:
xhosa
'zulu's close' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'relative has ox to transport' is the wordplay.
'has ox' anagrams to 'XHOSA'.
But, I am not clear how the anagram is indicated.
Can you help me to learn more?
(Other definitions for xhosa that I've seen before include "Member of a Bantu-speaking tribe" , "South African tribe" , "South African cattle-rearing people" , "Tribesman" , "Clicking tongue" .)