Some conversed in Gaelic (4)
I believe the answer is:
erse
'gaelic' is the definition.
(I know that gaelic can be written as Erse)
'some conversed in' is the wordplay.
'some' indicates a hidden word (some parts of the word are used).
'ERSE' can be found hidden inside 'conversed in'.
(Other definitions for erse that I've seen before include "Possibly the language" , "Old language spoken by strange seer" , "Old Gaelic for the seer" , "Old name for Celtic languages" , "Kind of Gaelic for seer" .)