This is a list of resources put together by Osian Jones. The content of the links have been written by others. I found out about them through people sharing their knowledge.
Digital Service Standard for Wales
MoJ - The Modernising Power of Attorney team’s approach to Welsh language content and testing
Summary blog post of CDPS’ trio writing pilot
Heledd Quaeck’s personal reflection of Natural Resources Wales’ evolution of bilingual design
How to do trio writing - a guide
How to do pair writing and trio writing on YouTube
Research with 144 Welsh language users at the 2022 National Eisteddfod
CDPS’ Trio writing pilot findings report