It is acceptable to use 'they' as singular when referring to 'a person.' Works: "When a person reads, they learn" Doesn't work: "When Jim reads, they learn"

It is acceptable to use 'they' as singular when referring to 'a person.' Works: "When a person reads, they learn" Doesn't work: "When Jim reads, they learn" It also works for other non-proper nouns like "When a knight enters the room, they kneel". I think this is mostly an artifact of implying "When knights enter the room, they kneel." I feel like this also works: "When the author wrote x, they were really saying y". I'm sure there's some explanation for it, but it's generally okay to use 'they' in the singular and anyone that disagrees is some snobbish weirdo. It clearly conveys what one means which makes it suitable for use, IMO.