Examining French grammar in light of my teaching my granddaughter French, I learned just how much the expression ‘one Xs’ dominates the verb paradigm. “on est” translates “one is” but not well, for “on est” can mean “he/she/it is”, “you are”, “I am”, most assuredly “they are” and almost 90% of the time, “we are.” “on boit le cafe” is good for Spanish “se toma el cafe”, both expressions which are hard to translated into English except as “one drinks coffee, coffee is drunk, they drink coffee, we drink coffee,” and other awkward phrasing.
What is amazing to me is how in everyday French (francais populaire), it shows up in ways difficult to explain in third year French classes. For example, I was watching the French language mystery series, Astrid, they showed a photo of two women we knew (on savait) to be a lesbian couple. On the photo was inscribed “On est belles, mon amour.” I would translate that as “we are beautiful, my love.” Grammatically “on est” is singular but “belles” is not only plural but feminine, as befits the sex of the two women. Then “amour” itself is a masculine noun requiring a masculine possessive adjective but would be “mon” anyway because “amour” starts with a vowel and therefore “*ma amour” is ruled out.
Yet French is listed among the “easier” languages to learn on the FSI scale.