Formal You (Vous)
I've noticed that Duolingo leaves out the conjugation of the formal you (vous) in the French lessons.
Typically it's something like:
Je suis Tu es Il/Elle est Nous sommes Vous êtes Ils/elles sont
But Duolingo always leaves out the Vous...does anyone know why?
It's there. Plenty of exercises on duolingo have "vous êtes" and "vous auriez" and such. You'll get to it eventually. Also, for any of those English "you" sentences you can write vous or tu and either one will be accepted.
Note that this flexibility is only from English, though. I've completed the French from Spanish tree and I'm currently completing the German from French tree and they're more picky. If the Spanish sentence says "usted" then it wants "vous" and if the Spanish sentence says "tú" then it wants "tu." Similarly, if the German sentence says "du" then it wants "tu" and if the German sentence says "Sie" it wants "vous." But that makes sense, because in those languages there are plural/singular and formal/informal versions.
One could argue that we should use "thou" for "tu" and "you" for "vous" but except for the Shakers and Quakers we did away with the informal "thou" a long time ago. Even modern Quakers and Shakers are starting to use you instead of thou. So our version of "tu" is pretty much historical. It's good to know it though. You need to understand when reading Romeo and Juliet for example, that when the patriarchs of the Montague and Capulet families meet in the town plaza of Verona, they're always calling each other "you". ("I am for you, sir!", "Do you bite your thumb at us, sir?") but later, when Romeo and Juliet are speaking with each other, it's less formal. ("Shall I compare thee to a summer's day? Thou art more lovely and more temperate." Notice the objective and nominative forms--thee and thou, respectively--in that excerpt. French uses "tu" for both, but if you study Spanish, you'll have to learn different informal forms for objective and nominative cases, because they are still used extensively in those languages, just like in Early Modern English.)
Edit: The part in red is false. (see below)
haha. yes, that's true. Good call. It's the COI and COD form, as well as the reflexive pronoun. Then there's the disjunctive form toi as well, as in "avec toi." I'm not sure what I was thinking when I wrote that.
Maybe I was comparing to tú, te, and ti in Spanish, but now that I think about it, I see that it's similar in French:
Tú vienes = Tu viens
Yo te doy = Je te donne
Gracias a ti = Grace à toi
Thanks for noticing that and pointing it out. Have a lingot and a flowchart for the T-V distinction: