Where to find teaching roles? Norfolk or Wales

maman

Welsh is taught in all schools in Wales. It's part of the National Curriculum. 

In some areas, particularly in the North, the whole curriculum is taught in Welsh. In the South, the curriculum is taught in English but with some specific Welsh language lessons every week.

Obviously, the younger the pupils the simpler the language lessons. 

As @housebuyer143 said, if you get a job in a shortage area then the school will help you to learn the basics or I have known some schools where a teacher can get cover for Welsh lessons. It's a bit like some schools buy in cover for games lessons while the class teacher has PPA time.