What is a standard polite answer to a stranger to ask about the purpose of their approaching me?

Question

When a stranger approaches me with a generic salutation without a specific request -- e.g., "Hi!", how should I politely inquire about their purpose or matter/ topic of addressing me ?

Directly it would be "what do you want from me?", but how to say the same politely? In my native language it is something like "How can I serve you?", but this sounds to me excessively submissive -- in fact I am not their servant; maybe "In what way can I help you?" ?; but this sounds to me too specific, as offering some service, i.e., as asking for being assigned a specific task, so that a natural expected answer to such a question understood too literally could be "two mugs of beer, please" (once in such a situation I got an answer "send me money" -- I guess it was a joke ridiculing the literal meaning of my question ) ; instead, I want to make it clear that my reply is just a generic polite formula with no literal meaning, i.e., I want to be nice to them, but not to offer my service really.

For example, if somebody messages me with a "Hi :)", an answer that I might expect to such a polite question that I am looking for, could be "professor, I am interested in studying PhD in your Lab under your guidance" or "I want to publish a paper in your journal", if this is the case i.e., if this was the motivation (subject / topic) of their contacting me. -- not "send me money" or "two cups of coffee, please".

Answer 1

It depends very much on the situation. Responses suggesting service are appropriate, if they come from a representative of a business or organisation to a private citizen. They are not a good choice in the other direction. Between private citizens, they used to be much more common, when one might ask for the other’s hospitality. But that is rare these days.

A less formal “what can I do for you?” is perhaps the only response of this sort that I would think is still typical. It implies that the speaker is ready and willing to have some of their time taken up by this unexpected enquiry.

“Can I help you?” is also an option, but I find that outside of a business context, it often has a negative connotation: “you clearly have a problem”, or even “you’re causing me problems, so I’ll ‘help’ you to go away”. (Within a business context, it’s generally fine: you can suggest that customers have a problem, if it’s the sort of problem you’re in business to solve!)

Politeness in English often takes the form of being indirect. Many questions can be made (more) polite by asking if you can ask. So instead of “what is this about?” (direct; not actually rude, but not trying to be polite either), you can say “can I ask what this is about?” (“May” instead of “can” is slightly more formal.)

If the situation is very informal, a typical response would be to simply invite them to talk: “Yes?” or “go ahead.” (“What’s up?” falls into this category too, but is probably friendlier than you want to be with a stranger.)

Answer 2

I would say, What's going on? to that stranger. Very simple. Very informal. Very common.

Answer 3

There is no standard response.

If someone strange contacts me on Skype with "Hi". Then I use the Skype tooks to block and ignore them. They are probably scammers and if not, well not my problem.

On a phone, I'd speak first. But if all they say is "Hi", I'd put the phone down. Again I'm not interested in chatting to random scammers.

In the street, I would probably not use English at all. I would turn to look at them, and raise my eyebrows. The "eyebrow flash" is a universal sign of I want/am willing to make contact with you, so invites the other person to speak.

I might use "Yes?". Paired with the eyebrow flash it implicitly Yes, I am ready to listen to you. Similarly "Uh ha" or some non-lexical sound, to mean I heard you, so please continue.

I might use "Can I help?" That is the most explicit question.

I might say "Sorry" to mean "Sorry I won't talk to you"

I might ignore them - that is rather rude, but they are a stranger and they don't have any right to talk to me about anything.

I would not say more. They are the person who is initiating contact, it is up to them to do the talking.

If this is a text message, my preferences would be ignore, "Yes?" or "Can I help?". In text, I would normally ignore messages from strangers.