라 쓰다

written X, read as Y

The real pattern is -(이)라 쓰고 -(이)라 읽는다/부른다, "spelled X but pronounced Y," a set-up for saying what something really is: [절친이라 쓰고 덤앤더머라 부른다], "written 'best friends', read 'Dumb and Dumber'." A quiz show uses it straight: 한국사라 쓰고 순발력이라 읽는 시간입니다. Several other lines here are not that at all — 아라써요, 모ㅎㄹ라써, 모라 써야 되지 are playful chat spellings of 알았어요, 몰라서 and 뭐라, where the syllables just happen to line up.

Register: joking; caption and chat style