Using ihr when speaking to one person
This is something for beginners.
Usually when we speaking to a friend, we use "du" - second person, informal, singular. But there are times when we can use "ihr" - second person, informal, plural.
Here's an example. Let's say you are speaking to a friend he says, "Meine Familie fahren nach der Schweiz." You can reply "Wann fahrt ihr?" because you are asking "When are all of you going?".
You are right, and your sentences are correct. Only this one should be corrected: "Meine Familie fährt in die Schweiz."
To make it clear that I'll be travelling, too, I would probably say: "Ich fahre mit meiner Familie in die Schweiz." Or, as a little girl, I would probably have said: "Mama und Papa fahren mit uns in die Schweiz."
And in this situation, you can very well ask: "Wann fahrt ihr?"
You can use "ihr" when you are talking to someone that you adress with "du", but talk to that person as a member of a group.
Another example: Ich arbeite mit Kollegen an einem wichtigen Projekt.
Meine Freundin fragt mich: "Wann müsst ihr das Projekt denn abgeschlossen haben?"
Heike, may I ask you to expand on this a bit
I was wondering what a native speaker's thought would be if 1) he tells another person "Ich fahre mit meaner Familie in die Schweiz." and 2) the listener then asks "Wann fährst du?" instead of "Wann fahrt ihr?". If the listener was NOT a native speaker, would the native speaker simply think it was a foreigner's mistake? If a native speaker would ask "Wann fährst du", what would the native speaker think?
I just wondered what a native speaker would think.
Hm, I think it would be OK to ask "Wann fährst du". It's a matter of focus. Maybe I don't know the family, and I'm only interested in when my friend will leave, so I might unconsciously ask only for that "du".
To me, the use of "ihr" in this situation sounds more embracing, warmer -- I acknowledge that my friend is in good company. The use of "du" sounds like separating this "du" from their company, but it is not wrong.
It's just a question of general "feel": The version with "ihr" sounds nicer.
(cross-posted with speising)
There are two more kinds of "Ihr" when addressing a single person:
(1) pluralis majestatis / majestic plural: Royals, e.g., were addressed by "Ihr" instead of "Du" or "Sie". The same traditionally holds for judges and other people historically addressed hyperformally ("Euer Ehren").
So Euch danach ist, werden wir Euch nunmehr ein Stück darbieten.
(2) colloquial "Ihr": In many areas of Germany, especially in the South, clerks, shopkeepers and salespersons are colloquially addressed as "Ihr".
Habt Ihr das auch in Größe 30 vorrätig?
This is special because by normal formal standards you would address them by using "Sie". This "Ihr" is usually meant to be friendlier, but not impolite at all. It will most commonly be read as the whole sales team being addressed.