Letter, I say (3)
I believe the answer is:
gee
This could be a double definition.
'letter' is the first definition.
(G)
'i say' is the second definition.
The answer and definition can be both to do with communicating as well as being verbs in their base form.
Maybe you can see a link between them that I don't see?
Can you help me to learn more?
(Other definitions for gee that I've seen before include "Goodness" , "Word of encouragement to a horse" , "Alphabet's seventh letter" , "American exclamation" , "Wow!" .)