No-one can change your language settings besides yourself. I checked a bunch of your new translations to see if moving would to cy would be possible but all checked translation exist in cy since years. So sadly I do have to mass-delete your translations into en-gb.
Thanks for your help. I logged in this morning, and got a message: 'Your language has now been changed from en-gb to Welsh. That confirms that my settings have been compromised. I've had many messages over the years that many attempts to log in under my name have happened. It seems this time someone has been successful. This is my last edit on translatewiki.net. Robin Owain (talk) 08:02, 13 July 2021 (UTC)