Language of many, in the end (5)
I believe the answer is:
tamil
'language' is the definition.
(Tamil is an example)
'many in the end' is the wordplay.
'many' becomes 'M' (Roman numeral for a thousand).
'in' means one lot of letters goes inside another.
'the end' becomes 'tail' (tail is a kind of end).
'm' placed within 'tail' is 'TAMIL'.
'of' is the link.
(Other definitions for tamil that I've seen before include "An official language of Sri Lanka" , "Dravidian people of India and Sri Lanka" , "Sri Lankan" , "Native of south India or Sri Lanka" , "Asian language" .)