When I was in school in the 80's, I remember seeing these books stacked up at the back of the classroom. There were other Ladybird books in English standard spelling (they were really common), but these were weird. The teacher just told us to ignore them. But weirdly, the text is really easy to read int he examples given. I never used or even read the ones in my youth, so it must just be easy for my brain to process (disclaimer, I am a speaker of basic Swedish and a little Norwegian, so I am used to reading words with odd spellings and going "oh right, that is X in English.")