I loudly call for sign you're paying attention (3,7)
I believe the answer is:
eye contact
'sign you're paying attention' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'i loudly call' is the wordplay.
'loudly' shows a homophone (sound like) (when spoken - not silently).
'call' becomes 'contact'.
'i' is a homophone of 'eye'.
'eye'+'contact'='EYE CONTACT'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for eye contact that I've seen before include "direct observation?" , "Communication" , "shared vision" , "Exchange of views" .)