Starts to have any indulgence in this Tamil month when 1ac comes (4)
I believe the answer is:
thai
'this tamil month when 1ac comes' 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?
'starts to have any indulgence' is the wordplay.
'starts' indicates taking the first letters.
The first letters of 'to have any indulgence' is 'THAI'.
'in' is the link.
Can you help me to learn more?
(Other definitions for thai that I've seen before include "countryman" , "Sort of eastern cooking" , "oriental language" , "Citizen of the country once known as Siam" , "Native of Bangkok, say" .)