And in Llanybyther right on the Carmarthenshire/Ceredigion border, due to an influx of Polish people working in the abbatoir English is the number three language and seldom spoken - the children are either taught Welsh or Polish at home, when they go to School, the Polish kids learn Welsh then English with their Welsh colleagues, so there's hardly a need to use English there.
When I started in school back in 1971 neither of the two primary schools in the valley were dedicated 'Welsh schools' yet everything was taught through the nedium of Welsh, English wasn't taught until the third or fourth year and then as a separate subject a few times a week I couldn't speak English until I was five or six.