Show respect for nineteenth eleven, as you might say? (6)
I believe the answer is:
esteem
'show respect for' is the definition.
(to esteem is to respect)
'nineteenth eleven as you might say?' is the wordplay.
'nineteenth' becomes 'es' (I am not sure about this - if you are sure you should believe this answer much more).
'eleven' becomes 'team' (eleven or XI can mean a football team).
'as you might say?' indicates a 'sounds like' (homophone) clue.
'team' sounds like 'teem'.
'es'+'teem'='ESTEEM'
Can you help me to learn more?
(Other definitions for esteem that I've seen before include "Revere(nce)" , "Good opinion" , "credit" , "gain respect" , "'Regard, respect (6)'" .)