Nothing to read in old language (5)
I believe the answer is:
oscan
'old language' is the definition.
(I've seen this before)
'nothing to read' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'to read' becomes 'scan' (scanning is a kind of reading).
'o'+'scan'='OSCAN'
'in' is the link.
(Other definitions for oscan that I've seen before include "Language once heard" , "Extinct language of southern Italy" , "Old tongue" , "Ancient tongue" , "old Italian" .)