Cambrian (5)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cambrian</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for welsh that I've seen before include "Owain Glyndwr?" , "From Aberystwyth, for instancewelshw" , "Nationality of Dai or Ivor" , "From Swansea, say?" , "tongue" .)