Follow Frenchman in language (5)
I believe the answer is:
tamil
'language' is the definition.
(Tamil is an example)
'follow frenchman in' is the wordplay.
'follow' becomes 'tail' (both can mean to chase or pursue).
'frenchman' becomes 'M' (abbreviation for Monsieur).
'in' is an insertion indicator.
'tail' placed around 'm' is 'TAMIL'.
(Other definitions for tamil that I've seen before include "Dravidian people of India and Sri Lanka" , "Southern Indian language" , "Language of southern India and Sri Lanka" , "South Indian people or language" , "Asian language" .)