I think Duoliongo's translation is wrong, it shoud be 'I am going to tell them something'. The English sentence would be translated as 'Os voy a contar una cosa'. In Latin American spanish this construction is common. The pronouns are a bit different when your cross the Atlantic ;-)
As Dingisbroot said, the American English language uses "you" as 2nd person singular and "you" as 2nd person plural. You all is just a modifier of you. I'd never, for example, use "you all" or "y'all" in anything formal, because it sounds out of place where I live, and it can be better described by just saying "you." In
You have homework and I expect you all to do it, the "all" is modifying the 2nd person plural "you," and it's unnecessary.
You have homework and I expect you to do it makes sense too.
Basically, the "all" in "you all" or "y'all" is just a modifier of the "you." And that's about all it does.
Feel free to correct me if I'm wrong here.
I sometimes use "you-all" , but I would not say it is standard northern English.. I don't know anyone else who does use it..
I did borrow the idea from my southern friends.
Also, I believe, but may be wrong, that in the South, "y'all" can be used as a singular "you." This article addresses that question. http://mentalfloss.com/article/58782/can-yall-be-used-refer-single-person
English used to have a singular and a plural "you" (thou and you, respectively). These died on the chopping block to streamline the language and "you" became both singular and plural.
According to Wiktionary, "y'uns" is a contraction of "you" + (a form of) "ones." Try googling "etymology of y'uns." There is some interesting stuff there.
You should never be marked wrong for typing 'you' where it is plural. English does not distinguish between singular and plural 'you'. People have their colloquialisms such as 'y'all' and it's possible to say 'I expect you all to do it' but only to emphasise that 'every single person' should do 'it' but frankly, only 'you' by itself should be accepted as an answer for the plural so as not to confuse learners. Learners need to understand early on that 'you' is both singular and plural. No extra words are needed.
Sigh, ElleLingo, you (alone) are right verses us all, lol. (I was trying to be funny, but you do make a very valid point about the "correct" use of "you"). OTOH, we are not given context, and i hear and say "you all" frequently when i'm addressing several friends. (I'm also on a one person mission to stop the capitalization of "i" as "she", "he" and "it" are not capitalized, so why should i!!!). 201507
I am not saying it would not be understood. I am saying that it sounds weird. I am assuming that English is not your mother tongue, otherwise it would sound very odd to you, too. You may find it helpful to take a look at some of the numerous books available on "English usage". Good luck!
DrCord. I've read through the debate and I must ask: Are you a native English speaker? I imagine not given your belief that your sentence should be correct. Kazmax1 kindly tried to explain to you that it's wrong and not how English speakers would talk. You then disagreed with a native speaker and when proven wrong, you complained that it is obviously possible to prove someone wrong when you present them with evidence. Yes, yes it is.
Not only is your original sentence wrong ("I am going to tell a thing to you") - in fact, so is the additional example you gave ("I am going to tell something to you"). I don't claim to be a grammar expert so I'll hazard the guess that English prefers the indirect object to come before the direct object with 'tell'. Yes, you would be understood by English speakers and there's nothing wrong with speaking like that if you choose to. The point is that Duo is not teaching you 'pigeon English' or 'street English' or 'they'll get the gist English', Duo is teaching you correct English as far as possible. The correct answer is "I'm going to tell you something".
However, with 'say' the correct answer is: "I'm going to say something to you".
I am a well-educated native English speaker. I also excelled in honors English class while in school. The sentence "I am going to tell something to you" is perfectly grammatically correct. It is the exact same sentence you are defending as the only correct version "I'm going to say something to you". Tell and say are synonyms and are the same parts of speech. The other sentence is is also grammatically correct. "a thing" and "something" are basically synonyms (not technically, because "a thing" is 2 words, so it cannot technically be a synonym, but they mean the same thing and fill the same part of speech). Furthermore I looked each of these sentences up on English language grammar checkers and they come back as correct. You should consider doing research before presenting your guesses as definitive rules. You should also consider whether you intend to be very rude by not only deciding that I am a non-native English speaker, but telling me I speak in pigeon-english.
DrCord, you know perfectly well that I did not say that you spoke pigeon English. I said Duo isn't teaching it. Additionally, if you don't know that 'I will say you' is grammatically incorrect whereas 'I will tell you' is required then I'd question the standard of English required in your 'honors English class'. Nevertheless, given that you are an English language expert, you do not require any assistance from anyone here regarding your original sentence and you yourself will be able to figure out why it was wrong. By 'wrong' I do of course mean 'not common usage'.
Finally, I did not present my guess as a definite rule, I quite clearly stated that I wasn't a grammar expert and that I was just hazarding a guess so I'm afraid that your response really made no sense whatsoever.
Don't let him get to you. We know you are correct ElleLingo. I was going to stay out of the discussion but he is so RUDE and then calls others rude. He asks a question then acts like a jerk when it is answered.
If you already know it all DrCord why did you "ask" in the first place?
The only connection I see (for my own purposes of learning/memorizing) is the verb recount in English (although I don't hear/see it often).
tell someone about something; give an account of an event or experience: [ with obj. ] : I recounted the tale to Steve | [ with clause ] : he recounts how they often talked of politics.
Jeff, in your example, "them" is a direct object (the thing that took the action of the verb). Several people have explained in this thread that les,the Spanish word in the lesson sentence, is an INdirect object (le=singular you, les=plural you or them). It is the "clue" for you to know NOT to translate the verb as "count" (because "count" only takes a direct object), but to use the other definition "TELL you something." "Something" is the DO, & "you" is the IO. It is a similar use with the verb "read," when you say "I'm going to read you a story."
If re-ordered, you could mean the same thing to say, "I'm going to read a story to you." But the "to" is "understood," or silent, when you place it earlier in the sentence.
In Spanish, their sentence structure requires the IO to be placed before the verb and DO, if I remember their advice correctly. Hope that helps. :-)