Sing in Tyrolean fashion (5)
I believe the answer is:
yodel
'sing in tyrolean fashion' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for yodel that I've seen before include "Sing partly falsetto" , "Sing in high trilling tone like Swiss mountaineer" , "Sing in high pitch like Swiss mountain dwellers" , "Sing (Alpine folk music)" , "Sing in traditional Swiss manner" .)