Of those who did not have a fluent parent, the highest percentage, 34%, had started learning to speak Welsh in primary school, 31% in nursery school and 10% in secondary school.
O’r rhai nad oedd ganddynt yr un rhiant rhugl, roedd y ganran uchaf, 34%, wedi dechrau dysgu siarad Cymraeg yn yr ysgol gynradd, 31% mewn ysgol feithrin a 10% mewn ysgol uwchradd.