I've corrected and added to the existing Welsh front end translation. The only line I haven't done is
JEV_EVENT_WEEKOPT=Week(s) of a month repeat type week
I couldn't quite work out what this line meant and I can't find where it appears. I may do the back end sometime but I've got a couple of other things to do first.

The website I'm working on is now online at
http://www.popethcymraeg.com