Doctor able to speak and explain further (9)
I believe the answer is:
elaborate
'explain further' is the definition.
'doctor able to speak' is the wordplay.
'doctor' is an anagram indicator.
'to' says to put letters next to each other.
'speak' becomes 'orate' (I've seen this before).
'able' is an anagram of 'elab'.
'elab'+'orate'='ELABORATE'
'and' is the link.
(Other definitions for elaborate that I've seen before include "Complicated - complex" , "Explain details" , "Develop in more detail" , "Add details to clarify meaning" , "Detailed, complicated" .)