it seems odd that an English colloquialism of "on us" would translate directly into Hebrew using the preposition for on. Is that maybe because this phrase is just lifted straight from English, rather than folks in Israel saying something more explicit like "the meal is our treat" or "we'll pay for the meal" or "we're buying" or "we're paying" or "the bill is ours", etc. ad infinitum
There is something similar in Greek as well, we say «Το πήρε πάνω του», "He took it on him". This means that he takes responsibility for getting something done, or for having done something. It might also mean something different and a bit negative, that he is thinking (too) high of himself, the "it" in this case usually being a good result or a compliment.
Nope, even Classical Arabic uses it. English didn't even exist yet when Islamic texts were taken down. I'd say it's the other way around: it's "odd" that this is an expression in English in the first place. Us Semites, we use the preposition "on" to indicate responsibility very frequently. Because we generally tend to use preposition where English would use verbs on multiple occasions (compare "have" and "yesh"). This makes more sense as an idiomatic usage in Semitic languages than it does in English.
אני צריך כוס קפה! Despite being quite familiar with the Hebrew word ארוחה, I translated it "The lion is on us!" האריה עלינו! Well, at least the meaning of this Hebrew sentence turned out more positive than the one with that ילד אומלל in the previous lessons: האריה אוכל את הילד! זה חבל מאוד!
It’s arukhah. To me, the Hebrew r is made so far in the back of the throat that it sounds like awukhah. If you’re used to the American r which is made with rounded lips or the Spanish r which is made at the front of the mouth, it takes practice to hear the Hebrew r. He pronounces the r the way Israel is usually pronounce it.