The translation is gramatically incorrect in English. This is not how a native English speaker would say this, they would say "you are all humans"
To keep the same emphasis, that would be ihr seid alle Menschen.
The Duolingo translation is because a recent change to how practice sentences are created keeps insisting on ihr = "you all". I don't think there's an especially good-sounding way to translate this accurately into English, but simply "you are humans" should suffice.
Ich = I Du = Thou Er, sie, es = He, She, It Wir = We Ihr = Ye Sie = They Sie = You »formal«
That was actually how early English personal pronouns were; it was still quite similar with other conservative German languages such as German »Hochdeutsch« and Icelandic »Íslenska«, and, of course, Ænglisc was the medieval germanic language spoken by the Jutes, Angles and Saxons with dialectal variations on what is today England and Great Britain.
Yeah. Just came to say the same thing. Not sure if you all are is wrong but it's not as common
As written on Duolingo's grammar pages, en is used to pluralize feminine nouns, but Mensch is a masculine noun. Seems like an exception to this rule... Interesting!