Fail to pay gambling debts? The language! (5)
I believe the answer is:
welsh
'language' is the definition.
(Welsh is an example)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for welsh that I've seen before include "Cymric" , "British language" , "From Aberystwyth, for instancewelshw" , "Native to, eg, Cardiff" , "Dresser, harp or rabbit" .)