The plural of person is people in this situation. Persons seems to refer to physical bodies in official or formal contexts, for example "This vehicle can carry 7 persons maximum." or "No persons admitted without a pass." or "There were drugs found on their persons." or "Missing Persons Bureau"
"Person" refers to an individual. "persons" is a plural that is used in very few expressions in America. "People" is the more common plural and would be used here. Thank you, a10gac below for reminding me that persons is still in use in certain instances. http://www.merriam-webster.com/dictionary/persons http://dictionary.cambridge.org/dictionary/british/missing-person?q=persons http://www.oxforddictionaries.com/definition/english/person?q=persons
Unseres could be used for neuter objects (like das Buch) when the noun itself isn't mentioned. Have a look at this example:
Keiner mag dein Buch. Viele Menschen mögen unseres = "No-one likes your book. Many people like ours".
In this way, it works like "our/ours" in English:
Unser Buch ist unseres = "Our book is ours".
You can't write unseres Buch here, for the same reason you can't write "ours book" in English.
Strong inflection, plural, nominative case.
Or, follow this flowchart: http://www.nthuleen.com/teach/grammar/adjektivendungenexpl.html
Or, think about it like this: Viel- is being used as an adjective to describe Leute. Because the adjective is in front of the thing it's describing, it needs to be inflected (the ending must be changed in ways that match the noun). The noun, Leute, is plural. It's also in the nominative case (the subject of the sentence). Plurals in the nominative case use the definite article die (as opposed to der, das, etc.), and so the ending of this article (-e) has to show up somewhere in the inflection. Since there's no article (it's not die ... Leute), then the only place this inflection can go is directly at the end of viele. When the adjective gets the same ending as the definite article would have, it's called 'strong inflection'.
Menschen can also translate to "people" (i.e. it is not only used where you would say "humans" in English). I'm still waiting for a clear explanation though, as I haven't found a good one on the web yet. Someone else already asked this question, though, so you can help prioritise that by upvoting it.
Because viele means "many", not "every". "Many" means "a large number of something" but "every" means "all of something, without exception". Note also that you use "many" with the plural form ("many people") but "every" with the singular form ("every person"). It works similarly in German.
unser doesn't follow the same pattern as dieser? I'm confused on this, what is the distinction here?
Acc: Masc/Fem/Neut/Pl = diesen/diese/dieses/diese
How is it different for unser? Is it a different kind our pronoun from dieser? These sorts of ambiguities are what throw me off! Using that chart above it would seem to have to be "unseres"... of course it isn't; and that's what is confusing me.
Unser in this case is a dependent pronoun whereas dies- would be an article. https://deutsch.lingolia.com/en/grammar/pronouns/possessive-pronouns
Yes, things are not consistent for articles and pronouns or even different types of inflection, but unfortunately these are nuances you just have to learn. Although I don't recommend you worry about this now as duolingo doesn't address this, just remember that relative pronouns (look like definite articles) change in the genitive.
I feel like this is better said with Leute, rather than Menschen. It’s many PEOPLE, not many HUMANS.
Many (what?) like our book. Many in this case is an adjective, so simply "Many like our book" would not be proper English either. I beleive that is why it was not accepted here. It could have been "many dogs like our book" or "many critics like our book", or "many children like our book." But the speaker told us many "people" like our book.
In English "Many like our book." would be understood to mean "Many people like our book." just like when we say "Come here" and it is understood to mean "You come here." However, to learn the language, I feel we should be translating the words given for practice sake.
I happen to be an English teacher, so I completely agree with you. Duo experts do their best I believe, they cannot just pay attention to everything, though. I still think the German speakers confidently use their "Germanic" sense of grammar. I used to correct legal texts used by the EU, and I could always guess when they had been written by Germans. :-)