I didn't know that the -(e)ni suffix indicated the plural command. Now it makes so much sense that people would ask (a group of other people) "How are you-ni?". It's a really useful way to indicate the plural you in English!
Lol what? You mean Swahili? Intereating I have never heard this before!
I mean that it's useful to adapt this way of pluralizing into English, because English is so limited in the way to express who you are addressing (except for y'all, which often makes it sound like you're from Texas)
There's also you guys (to both male and female groups), youse, which is New York City, all y'all, which is also southern for large groups, etc. This lesson is very inconsistent, sometimes it requires the pronoun, sometimes it doesn;t, sometimes it doesn't allow it.
No native English speaker would say. Just indicate whether the command is singular or plural in parentheses.
I don't understand, in what context would anyone say "You all, look at a book"? A teacher could possibly encourage the students to look something up in a book but if you look at a book it sounds to me as if you don't read what's written in it, you just look at the cover. Silly thing to say imho.