What makes you think 15000 hours of listening would improve anything, more than spending those 15000 hours on any other activity ? And do you have any specifics results that could give credit to your theory ?
For reference, it is estimated that for hard languages, ~2200 hours of practice is required : https://linguapath.com/how-many-hours-learn-language/
There are a number of reasons why you would want to focus on input early on. For starters, with very little exposure to a language, you have very little idea of what it is supposed to sound like. Not just pronunciation but word choice, grammar, and phrasing as well. So when outputting early you will make your best effort attempts, which are almost certainly going to be incorrect. Odds are these poor "best effort" attempts will stick as muscle memory and continue to be bad habits well into fluency, if you make it that far. I'm sure you've encountered many foreign speakers in English that are very fluent but have poor pronunciation or use incorrect grammar.
I've never heard that "producing" a language is more efficient to learning it than "consuming" it. How can you learn anything by producing it without having "consumed" it first? That's not learning, that's inventing, and you don't want to be in the business of inventing language unless you're William Shakespeare. If you're interested in learning more about this idea, check out Stephen Krashen's Input Hypothesis [0]. In particular this quote from the Wikipedia article is salient:
> Talking (output) is not practicing. Krashen stresses yet again that speaking in the target language does not result in language acquisition. Although speaking can indirectly assist in language acquisition, the ability to speak is not the cause of language learning or acquisition. Instead, comprehensible output is the effect of language acquisition.
[0] https://en.wikipedia.org/wiki/Input_hypothesis#Input_hypothe...
That's all muddied by AI/programmed learning (how much connection do you get from Duolingo?) now but I think the kernel is still true. People largely learn languages to talk, not to listen, it's no wonder things are structured that way and good luck trying to sell people otherwise.
Though I do think there is value in watching tv series or movies you've already seen in another language _without_ subs. You're able to focus more on the dialog and pair it against your knowledge of the story structure without getting distracted. You can't only do that however, which I don't think you're suggesting. You need to have studied the language to know what words you can pick out/know/dont know.
This is only relevant if your goal is fluency and not having think so much before speaking.
…but let’s face it: either extreme (only input, only output) is clearly stupid.
Predictive models require a feedback loop; if you don’t have any means of correcting the predictions of good output, you’ll never refine your model.
This is true of AI models, and it’s true of humans. It can’t not be true.
The point is that you can only learn meaningfully from annotated inputs, like tv, or like talking to people. The input just has to be at the right level.
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Should people start with listening instead of talking to people? Probably not. Probably they should do both. Why not do both? It's crazy to suggest you should only one or the other.
Probably, the feedback loop in deep immersion of a language, where you have it around you all the time, in a country where that is the native language is the best possible way to encounter lots of examples at lots of different levels to learn from. Probably, you get better input from speaking, because it means people talk to you at a level similar to what you're already at.
Is it about actually speaking? No.
…but it’s patently ridiculous to suggest you could go to another country and just sit silent and listen for three months.
This is pretty interesting tech, and frankly, amazing that it works at well.
Is it perfect? No. Is it another useful tool? It certainly is.
If you can't grab hold of context of what's being said you won't really pick much up.
That's why total immersion isn't effective for beginners.
I'm unconvinced to be honest, as pretty much everything else that human learn is made better by practice, but I'm not a linguist.
I still think that proposing to start learning a language by spending 15000 hours (or 1500, or 150) listening to it, instead of trying to practice early on is a very inefficient way to learn a language, compared to pretty much anything
I'm sure speaking helps most people who study languages simply by exposing them to more input more frequently then they would otherwise be exposed to. I just don't think it is as efficient as focusing on listening first. It will lead to having an accent, grammer issues and pauses to think about how to say things.
That being said good luck finding any program that doesn't focus on speaking early.
Working in Sweden, where tech companies speak English internally, I've been able to follow the language learning journeys of quite a few people (including some using the strategy "don't bother"), and the people who end up the best speakers (with regard to accent, grammar and vocabulary) are invariably those who try to speak the language as much as possible as early as possible.
Yes, they will have a strong accent in the beginning, but it goes away with time (though accents rarely disappear entirely). The native English speakers who've lived in the country for twenty years without speaking much Swedish daily still have strong accents.
But that may not be that realistic for most at least not without a accommodating and capable tutor.
My anecdote - learning Mandarin, which is tonal, is absurdly hard before you develop an ear and tongue for tones. I think trying to practice speaking in tones helps to then hear them, because you understand the sounds people make better. How they abbreviate/slant or modify tones based on surrounding tones - why? Because it feels better in the mouth. So until you experience that, you won't understand slant tones and such.
Also, when you are reading you are most likely speaking with your inner voice. If you don't know the proper pronunciation, you may reinforce bad intonation/pronunciation habits. It happens to me when I'm reading a text with names that I'm too lazy to properly read. I just register the shape of the word with the first/last letters and length, then I pattern match in the rest of the text to know who we are talking about and that's it. More then once when talking with friends about books/articles/..., I could not tell the name of the person of interest. If it was written I would recognize it but I couldn't vocalize it.