It depends on the community, but the current meta among serious (non-casual) language learners is 1) comprehensible input, 2) extensive reading, 3) sentence mining, 4) spaced repetition + active recall
> what's to back up they're better?
Unfortunately... just the anecdotal experiences reported by these learners. I've talked with hundreds of successful language learners who reached actual fluency using these methods and I'm also one of them. Unfortunately, as many people online like to point out, these anecdotes are not technically scientific so there is a bit of "faith" you have to put into these methods. (Also, there is some debate in the field of SLA (second language acquisition) as to whether we will ever have a truly scientific model of SLA. If you're interested in this question, I'd recommend checking out the book "Key questions in second language acquistion")
In general, my advice to any serious language learner is you're gonna have to experiment a lot to reach fluency. Language learning takes on the order to thousands of hours and requires a vocabulary of over 10,000 base words for functional fluency (don't believe the youtubers who say you only need to know a couple hundred words. I've run the math on this way too many times)
One resource I like for finding comprehensible input is: https://comprehensibleinputwiki.org/wiki/Main_Page
One document I found particularly helpful is Paul Nation's "What Do You Need to Know to Learn a Foreign Language?": https://wgtn.ac.nz/lals/resources/paul-nations-resources/pau...
It has a lot of practical advice. In particular, he recommends reading graded readers books.
Inspired by that, I’ve also been building a free (open-source code + CC-licensed texts), community-driven website for interactive graded readers. Think Choose Your Own Adventure in your target language: you read simple stories, make choices, listen to audio, and check translations only when needed.
It’s still early (just a couple of stories so far) and definitely not a full language learning solution, but the goal is to create enjoyable input for learners. Would love your feedback if try it out: https://lingostories.org
Remember that first week is 20-30 hours of classroom time plus homework. That by the time you are done with that first week you already have most of a semester of regular classroom behind you.
Your experience is common. However it is mostly a reflection on you and your situation. You could have picked the language up much faster if you tried.
Note that I'm not intending to judge you. It is likely you have a life and other things to do with your time. Only you can figure out what is the right time balance for you (though once in a while something happens that would make you regret your decision)
I often wish the locals here would refuse to use English, but I enjoy speaking other foreign languages when I get the chance, so I understand when they want to do the same.
unfortunately the above is not a joke. It is what many people are really doing. The question itself is fine but don't let it consume you. Or if it does at least do as I do: confine your research to the language you are trying to learn.
That is actually much less of a problem in Duolingo where those sentences warry and that has you do variety of exercises.
Of course the number of cards is finite, but so are Duolingo's example sentences, so whether you get more or less variety ultimately depends on the size of your deck.
They will download a dect with single words translations rsther then spend a lot of times doing own deck with special features. That is done by people who primarily learn in another way and use anki as memory refresher.
Anki is great memory refreser, but that is not what was asked here.
To your last paragraph, you do set number of cards per day. Even if you have many different sentences on many different cards, they will graduate independently from each other. So, you will still see the exact same sentence a lot rather then getting different sentence each time you see the card.
More important is that practically Duolingo did not caused me to have any particular sentence or translation super strongly burned into my head. Maybe it is variety, maybe something else, but practical result was just not that.