US-English has a ton of greetings that don't mean exactly what they state but have purposes and subtle meanings. Regional English (as opposed to trade English, which just picks up whatever baggage the speaker's native language has, god this language is weird) is sort of a nightmare trying to learn or, and I'll try to grab the source for this, for people with an ASD.
Example: "What's up?" one of the standard informal greetings. The expected reply is "nothing much", but it leaves room for further conversation. Something to ask a bored friend.
"What's going on?" An inquiry that demands explanation for an event or action the other person is implied to know about. Your sister is crying when you talk to her, or you get an email that something went wrong at work.
Translate the slang and they mean THE EXACT SAME THING, but contextually, they lead to different conversations. For a supposedly informal language, there are a ton of very specific scripts one is expected to know.
Example: "What's up?" one of the standard informal greetings. The expected reply is "nothing much", but it leaves room for further conversation. Something to ask a bored friend.
"What's going on?" An inquiry that demands explanation for an event or action the other person is implied to know about. Your sister is crying when you talk to her, or you get an email that something went wrong at work.
Translate the slang and they mean THE EXACT SAME THING, but contextually, they lead to different conversations. For a supposedly informal language, there are a ton of very specific scripts one is expected to know.