Following the Welsh Language Use Survey 2013-15, the original intention was to conduct the follow-up language use survey between July 2019 and March 2021, namely the Welsh Language Use Survey 2019-21.
Yn dilyn Arolwg Defnydd Iaith 2013-15, y bwriad gwreiddiol oedd cynnal yr arolwg defnydd iaith dilynol rhwng mis Gorffennaf 2019 a mis Mawrth 2021, sef Arolwg Defnydd Iaith 2019-21.