Why do we say human “beings”? We don’t say dog “beings”, giraffe “beings”, or ladybug “beings”? (Or does that happen in other languages?) We don’t even say tree “beings” or desk “beings”, even though they exist as much as humans do.
I tried Googling this, and couldn’t find an answer.
Because “human” was originally an adjective, not a noun. So you need a noun of some sort (a “being”) to bestow the characteristics of human-ness upon. Over time, we began using “human” as a noun, and the “being” part became redundant.
Much like “microwave oven” eventually came to be called just “the microwave” and “sexual intercourse” eventually came to be called just “sex.”
Anyway, that’s my interpretation, for what it’s worth.
I like that; it makes sense. (I’m reminded of a famous etymologist who said that if an etymology makes sense, it’s very unlikely to be correct, but I think he was being at least partially facetious.)
Today, we say “human being” as a legacy of the past. I believe we can always replace it with the modern noun “human” without changing the meaning. It’s a relic, but one that we’ll continue to see for a long time.
Some languages have categorical markers to indicate whether something is, for example, an animal. Pretty sure humans don’t get that marker. Also, I think both German and Vietnamese use different words for “eat” depending on whether a human or animal is eating; using the animal verb for a human is very insulting.