Researcher wanting this instruction to make tea? (9)
I believe the answer is:
doctorate
'researcher wanting this instruction' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'to make tea?' is the wordplay.
'to' becomes 'doctor' (I can't explain this - if you can you should give a lot more credence to this answer).
'make' indicates anagramming the letters.
'tea' with letters rearranged gives 'ate'.
'doctor'+'ate'='DOCTORATE'
Can you help me to learn more?
(Other definitions for doctorate that I've seen before include "Highest degree in university" , "Highest academic degree" , "Academic qualification" , "Postgraduate degree" , "High degree" .)