It means current English medium schools can still teach English from the age of three, but now have the duty and opportunity to introduce Welsh from age three as well.
Mae'n golygu y gall ysgolion cyfrwng Saesneg cyfredol ddysgu Saesneg o 3 oed o hyd, ond erbyn hyn mae ganddynt y ddyletswydd a'r cyfle i gyflwyno'r Gymraeg o 3 oed hefyd.