Port and smack served up by a head of languages (5)
I believe the answer is:
natal
'port' is the definition.
(I know that Natal is a port)
'up by a head of languages' is the wordplay.
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'by' becomes 'at'.
'a' becomes 'an'.
'head of' suggests taking the first letters.
The first letter of 'languages' is 'l'.
'at'+'an'='atan'
'atan' reversed gives 'nata'.
'nata'+'l'='NATAL'
'and smack served' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for natal that I've seen before include "Relating to birth or the buttocks" , "old province" , "Province at one time" , "Relating to the time of one's birth" , "Of birth; former African republic" .)