Old letters in English among works (5)
I believe the answer is:
runes
'old letters' is the definition.
(I've seen this before)
'english among works' is the wordplay.
'english' becomes 'E' (abbreviation).
'among' is an insertion indicator (inserted letters are placed among others).
'works' becomes 'runs' (run can mean to function or work).
'e' placed within 'runs' is 'RUNES'.
'in' is the link.
(Other definitions for runes that I've seen before include "marks on old tablets" , "Old letters" , "old characters" , "Small stones bearing symbols with magic significance" , "Mysterious letters" .)