through the medium of

NEU Cymru said minimum targets on English-medium schools could have an "adverse effect on staff, especially if staff aren’t confident in teaching through the medium of Welsh".

It added: "Our Welsh in Education Workforce Plan sets out the steps we will take to increase the number of teachers who can teach Welsh as a subject, or teach through the medium of Welsh."

The 12-day event's closing film will be Piece by Piece - a documentary and biopic which explores the life and work of Pharrell Williams through the medium of lego animation.

Welsh language skills and education would also be increased in schools taught through the medium of English.

Recruiting teachers to train through the medium of Welsh and in subjects such as modern foreign languages and the sciences have faced the biggest challenges.