Old Scottish farmworker, initially identifying Asian language (5)
I believe the answer is:
hindi
'asian language' is the definition.
(one of the languages of India)
'old scottish farmworker initially identifying' is the wordplay.
'old scottish farmworker' becomes 'hind' (historical Scottish term for a farm worker).
'initially' indicates taking the first letters.
The first letter of 'identifying' is 'i'.
'hind'+'i'='HINDI'
(Other definitions for hindi that I've seen before include "An official language of India" , "Language derived from Sanskrit" , "Asian language" , "tongue" , "Indian language" .)