Language of one place to the north (4)
I believe the answer is:
tupi
'language' is the definition.
(Tupi language is an example)
'one place to the north' is the wordplay.
'one' becomes 'i' (Roman numeral).
'place' becomes 'put' ('put' can be a synonym of 'place').
'to the north' says the letters should be written in reverse.
'i'+'put'='iput'
'iput' in reverse letter order is 'TUPI'.
'of' is the link.
(Other definitions for tupi that I've seen before include "Amazonian language" , "Amazon language" .)