You say your friend’s name. They say 왜? (wae). You look it up: “why?” You spend the rest of the day wondering what you did.
왜? in response to your name is the standard neutral answer, roughly “yeah?” or “what’s up?” It isn’t a demand for justification.
The full set
왜? flat and neutral, between friends. The default.
왜~? stretched. Warmer, softer, a little playful.
왜? 무슨 일이야? (wae? museun iriya?), “yeah? what’s going on?” The follow-up makes the intent obvious.
응? (eung?), softer than 왜, more attentive. Closer to “hmm?”
어? (eo?), similar, a touch more casual, often used when you’re half paying attention.
네? (ne?), the 존댓말 answer, and the one you use upward.
왜요 keeps the edge
왜, 응, and 어 are all 반말. 네 is the polite one. 왜요? (waeyo?) sits in an awkward spot worth being precise about.
왜요? isn’t forbidden. People say it, and it’s grammatically polite. But as a response to someone senior calling your name it doesn’t land as “yes?” It lands closer to English “What?” Not the neutral one that means you didn’t hear. The other one, with a little edge on it, where you’re questioning being summoned at all.
That comparison does the work, because English speakers already know exactly how “What?” differs from “Yes?” when a manager says their name. Same information, completely different posture. The 요 makes it polite without making it neutral.
So: peer or younger, 왜 and 응 and 어 are all fine. Senior, older, boss, professor, customer, use 네. 왜요 is available when you actually want the edge, which is rarely.
What I can’t explain is why 왜요 keeps that edge when 요 defuses so many other phrases. My guess is the pushback lives inside 왜 itself where politeness marking can’t reach it, but that’s a story I’ve told myself rather than something I can show.
응 and 왜 aren’t identical either
Both are fine among friends and they aren’t interchangeable.
응 leans warm and receptive. 왜 leans brisk and slightly guarded. A friend calls your name and you’re in a good mood, 응 fits. You’re busy, 왜 fits. Neither is rude, and people do read the difference.
Tone carries most of it anyway. A flat 왜? is neutral. A clipped 왜 with no rise at the end is annoyed, and everyone hears it that way. That part isn’t Korean-specific.
Worth keeping separate: everywhere other than response position, 왜 still means exactly what the dictionary says. 왜 그래? (wae geurae?) is “what’s wrong?” 왜 안 왔어? is “why didn’t you come?” Nothing has drifted there. The attention-token reading only exists in the narrow slot right after someone says your name, which is why it feels like a different word when you first meet it.
Things not to do
Don’t use bare 왜 upward. The 요 at least keeps it polite; without it you have 반말 plus an edge, which is two problems stacked.
Don’t repeat it. 왜? 왜? reads impatient rather than doubly attentive.
Don’t drift mid-conversation. If someone senior calls you, you answer 네, and they start explaining something, you don’t switch to 왜 for the follow-up. Hold the register you opened with.
The practical version: make 네 your reflex for anyone you don’t already 반말 with, and let 왜 stay with people you’re genuinely casual around. Recognize it constantly, because it’s one of the highest-frequency words in spoken Korean. Just don’t reach for it under pressure.
Romanized: wae, occasionally way or weh in casual transcription. Pronounced [wɛ], one syllable, closer to English “weh” than “way.”
The 응 versus 왜 warmth split is the piece I’d most like tested. If a friend has ever answered you with 왜 and it felt cold when you expected 응, I’d like to know what the situation was, because I suspect the difference is stronger in some regions than others and I have no way to check that from where I sit.