Yours is the first comment I strongly agree with; as a multilingual/bicultural Asian American, children don't have this supposed difficulty hearing tones.
Most of it is passively paying attention. It should not be a struggle, it's one of those the more you struggle and overintellectualize the less time you are focusing on paying attention and letting your hearing ability do its work it was evolved to do.
The other thing is this whole emphasis on accents is misdirected. Teachers do not place this excessive emphasis on accents, it is people who want to sound "authentic" which is not a very wise goal of language learning in the first place.
I do think that learning music can help a little, especially a sonically complex instrument like violin and the like.
(caveat: I'm way oversimplifying on my Saturday afternoon, but that's my tentative views on this that I would try to argue for.)
I agree on not over-intellectualizing the tones.
I've seen people struggle to pronounce a word when I explicitly tell them what tones it contains, but then pronounce it perfectly when I ask them to just imitate me.
But I disagree about accents. One of the major flaws in most foreign language education, in my opinion, is that pronunciation is not emphasized heavily enough at the beginning. Being able to pronounce the basic sounds correctly has a huge impact on how native speakers perceive your language skills, even if you're not very advanced in the language.
> Being able to pronounce the basic sounds correctly has a huge impact on how native speakers perceive your language skills, even if you're not very advanced in the language.
That's true, but it counsels against trying to develop better pronunciation early.
If you sound like a native despite having just started to learn the language, people will naturally conclude that you are mentally retarded.
That's better than locking in a strong accent the rest of your life. Once you learn to speak a language, it's very difficult to fix your accent.
There are two problems with this:
(1) It doesn't get any more difficult to fix your accent. But most people won't, because there's virtually no benefit to doing it.
This is related to
(2) Once you learn to speak a language, you're not at any risk of people thinking that you can't speak it, even if you speak with a strong accent.
It does actually get much more difficult to fix your accent as you improve in a language. You have to significantly regress, slowing down your speech and taking pains to say everything correctly. You can lock in a good accent early on with much less effort.
There's really no risk in having too good of an accent early on. People will assume you're more advanced than you are, but once you tell them you're learning, they'll simply be impressed by your lack of an accent. There are worse things that could happen.