The proportion of households in which all usual residents said that English or Welsh was their main language varied from 98.8% in the Isle of Anglesey to 89.4% in Cardiff.
Ar y cyfan, yn 96.2% o gartrefi yng Nghymru (1.3 miliwn cartref), dywedodd pob preswylydd arferol mai Cymraeg neu Saesneg oedd eu prif iaith, sy'n gyfran lai nag yn 2011 (96.7%,).