Yes, it's the first person we hear (3)
I believe the answer is:
aye
'yes' is the definition.
('aye' means 'yes')
'the first person we hear' is the wordplay.
'the first person' becomes 'I' ('I' is a first-person pronoun).
'we hear' shows a homophone (sound like).
'i' sounds like 'AYE'.
'it's' is the link.
(Other definitions for aye that I've seen before include "Affirmative answer" , "Yes, at the double for the sailor" , "Yes; ever" , "Yes answer in voting" , "One voting in favour" .)