"Are you all giving my cat milk?"
Translation:Gebt ihr meiner Katze Milch?
Someone thought it'd be smart to mark the plural you by adding all to it so that users know that they need to use German ihr. Ever since, it has backfired.
(You could, of course, also use ihr alle, if you feel like it.)
Oh, I see. I tried "ihr alle" and it wasn't accepted, but now that I know what's going on, it all makes sense.
I realize that the Duo uses the English language phrase "you all" to indicate the plural. But it still rankles my brain every time I see it because it doesn't sound natural in English (native speaker here) and I've lived all over the States. Yes, there is a southern US expression "y'all" but that can actually be singular as well as plural. So not really the same thing.
If Duo does need a device to indicate second person plural how about "all of you?" No ambiguity there and moreover it is the title of a delightful Cole Porter song.
Y'all can go back to learning German now.
In my experience, y'all can only be singular when you're in Texas. In North Carolina, y'all is plural more or less exclusively. (I'm not sure where the geographic line is drawn between the two.)
In the part of Pennsylvania where I grew up, they have a word to fit the bill here: "yinz", short for "you'ns, which I guess is short for "you ones", although that was never really clear to me.