Language starts to worry English ladies staying here (5)
I believe the answer is:
welsh
'language' is the definition.
(I've seen this before)
'starts to worry english ladies staying here' is the wordplay.
'starts to' suggests taking the first letters.
The first letters of 'worry english ladies staying here' is 'WELSH'.
(Other definitions for welsh that I've seen before include "From a principality" , "Nationality of Dai or Ivor" , "Cambrian" , "Coming from Swansea?" , "From Swansea, say?" .)