See what others have to say (3-4)
I believe the answer is:
lip-read
'see what others' is the definition.
I can't judge whether this defines the answer.
'to say' is the wordplay.
'to' becomes 'lip' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'say' becomes 'read' (synonyms).
'lip'+'read'='LIP-READ'
'have' is the link.
Can you help me to learn more?
(Other definitions for lip-read that I've seen before include "How to "hear" when deaf" , "Dire pal can interpret mouth movements as words" , "Understand by watching (a person) speak" , "Understand without hearing" , "Interpret someone''s words when deaf" .)