It's not even just "indo-european" bias, it's just that word-for-word translation of sentences without any context only gets you so far. Even for something as "simple" as English-to-French it breaks down when the languages don't map 1:1 with each other.

For instance there's no single way to translate "I ran" in French, it could be "j'ai courru" or "je courrais" depending on context and depending no the lesson Duolingo will favor one or the other, leading English speakers to write puzzled comments like "I thought the imperfect was 'I used to run' or 'I was running', why is it 'I ran' here?" And the answer is "it's more complicated than that, but Duolingo won't teach you that".

Which is fine. It is about being understood. You are never going to get fluent from a course. Language changes, and even native speakers are learning new things.

That's besides the point. My point is "definiteness" is not a concrete concept in Turkish and if you're academically analyzing a sentence you'd have to use other types of information (accusative case, the word 'bir', context, etc...) to judge if a noun is definite or indefinite (or maybe something in the middle?). But Duolingo teaches as if this distinction is as strict in Turkish as it is in English. In English "a bear" and "the bear" are different things even without context whereas in Turkish "ayi" [bear] and "bir ayi" [one bear] mean more or less the same thing outside of a sentence and I'd just use "bear", but in some contexts they'll mean different things. "Ayi cikabilir" roughly means "caution, bear in area" and as you see you don't use "bir" but it is still indefinite. Duolingo would reject this answer. "Bir ayi cikabilir" would be Duolingo's answer, but it sounds awkward, no one would say that.

And there are no hard rules. In that sentence you can't just put +I to make it definite as I described above "ayiyi cikabilir" << this sentence doesn't mean anything. I think this is something your brain has to pick up implicitly while you're speaking/listening, I'm not sure if someone can discretely provide you a set of rules that always works. Just like in German you cannot translate "the" > "der". This is like Duolingo saying 'the'='der' and rejecting 'das' and 'die'.

So, it is not fine, it is wrong. And the wrong thing is not that Duolingo has a bug, it is that it has made-up grammar rules, which users still have to learn. If they never learned this rule, they'd be as well understood.

(I know you were replying to commenter discussing French, but I'm guessing something similar is going on)

Sure but my point was that Duolingo basing all of its courses on translating from one language to the other seriously limits its ability to actually teach you a language. My native language isn't English but as I'm writing these words I'm not translating, I think in English directly. If I switch to "translating" mode I'm a lot slower and I end up with unidiomatic English.

Any decent language learning course should try to immerse you in the target language as soon as possible, forcing you to actually think in the language instead of your own. There are many ways to do this, for instance making you answer questions. Instead of telling you "translate 'the cat is black' in French" they'd show you a picture of a black cat and ask you "Quelle est la couleur du chat?" and you'd have to answer "Le chat est noir". No English involved, like in real life. The problem of course is that such an approach is hard to correct by a dumb algorithm, especially as the concepts being taught become harder.

I disagree. The nuances that change are on a different level. I have learned a number of languages from books and this is taught pretty easily. If you can't conjugate a verb, you don't know much about that language.

>You add +I accusative suffix to [imply definiteness]

Very interesting! In Russian, the accusative suffix would play exactly the opposite role. While there's no real way to say the beer without additional context, you can say:

поставь пиво в холодильник / put the beer in the fridge

поставь пива в холодильник / put SOME beer into the fridge

пива (as partitive gen.) here sounds really weird to me, like you're pouring it out of a can into something else, and putting that in the fridge. If it's a can you can emphasise it with a number e.g. я поставил одну банку пива в холодильник :)

not a native speaker, just living and studying russian in moscow

It was noted below that this is properly called the partitive case; the Wikipedia articles have good examples in the vein of "А не испить ли нам чаю":[1][2]

[1]https://en.wikipedia.org/wiki/Partitive_case#Russian

[2]https://ru.wikipedia.org/wiki/%D0%9F%D0%B0%D1%80%D1%82%D0%B8...

The partitive here is to express that the speaker is not specifying in what form or shape the beer in the fridge should appear. For a native speaker it sounds like you are talking about some quantity of beer but omitted the quantity so it's literally just some unspecified quantity of beer.

So you would say that though? Like I've just never heard my хозяйка квартиры say that is all. I hear it often in things like "would you like some tea/beer?" etc or "i'm going to buy some tea/beer" but never like that. My impression was that outside of those contexts it's not popular. Mind sharing some examples? Would be really useful! :)

You probably would never hear somebody saying "Поставь пива в холодильник." since, while a correct sentence, it would need some rare circumstances to be said. Поставь here is much more concrete than "put", it's more like "place" and I could imagine saying this only if I had been managing the fridge at some party and noticed it's running out of beer so I requested somebody to add more beer there. Much more common would be "Принеси/достань/возьми пива из холодильника" (get some beer from the fridge).

>You probably would never hear somebody saying "Поставь пива в холодильник." since, while a correct sentence, it would need some rare circumstances to be said. [...] I could imagine saying this only if I had been managing the fridge at some party and noticed it's running out of beer

Yup, pretty much that. Or like that one time when we went binge-shopping on craft beers, but there was only enough space in the fridge for a couple of bottles; so that was a normal request about an hour before we were to watch a movie. Which is pretty much the exact situation you described :)

I think "пива" is the partitive case, though.

That's exactly it! [1]

I'm a native speaker, and I wasn't even aware of partitive case. They never taught us about it, even though a mind-numbing amount of time was spent cramming the name of the usual six cases into our heads.

I only got more interested in linguistics after moving to the US, and, sadly, only took one class in college on it.

Thanks for noticing this, I just learned something!

As a side note, I also mixed up genitive and accusative cases.

[1]https://en.wikipedia.org/wiki/Partitive_case#Russian

I think the definitive and most authoritative review of the Russian grammatical cases was done by Zaliznyak: http://inslav.ru/images/stories/pdf/2002_Zalizniak_RIS_i_sta..., in Russian, pages 36-55. Fascinating reading.

Having only learned Indo-European languages before, when to use "bir" was hard to get right in Turkish for me. But our teacher insisted.

That's not to excuse Duolingo obviously.

Articles are more of a regional feature, that is restricted to just a subset of indoeuropean languages. Articles work quite differently in Romance languages than in Germanic languages and even there are outliers like Icelandic which does not use indefinite articles.

In my opinion you could go even further an say that they have an English bias.

Funnily enough, the most ancient Indo-European languages have an incredibly complicated case system.