Translation:He can't dance.
I guess it's like the usage of 很
很 could be used for any of the meanings of "very" & "is (adjevtival)"
So i guess :
会 could both mean "will" & "can" at the same time . I'm not sure though..
But i think my fellow's answer to yours concerning "am going to dance" is better to provide a clear intention of "will "
I might be wrong, but before this, 会 has been used in sentences like ＂他明天会见我＂to show future tense, "He will see me tomorrow". Is the best way to know if it is referring to ability or time to see if a specific time is in the sentence? Like ＂他不会跳舞＂means he can't dance, but ＂他今天晚上不会跳舞＂means he won't dance tonight? Basically, how do you know the difference/say the difference?
Exactly what you said: by adding a time indicator. He cannot "not know how to dance" only this evening, so the only possibility is that he will not be dancing this evening. Similarly, if I say 他去年不会跳舞, the only possibility would be that he does not know how to dance last year (as last year is not consistent with 会 as a future tense indicator). 见我 is not an ability so 会 in this case can only be the future tense. The only possible confusion arises when 会/不会 is paired with an ability that can be learned, without any time indicator. This always means the subject having or not having the ability, never the future tense. For example: 他会骑自行车，他会去学校，他会骑自行车去学校。Only the first one is an ability to be learned, so it means "he knows how to ride a bike". 会 in the other sentences indicates future tense. Note that "riding a bike to school" is not regarded as an individual ability which can be learned.
他不会跳舞 emphasizes that he does not know how to dance / has not learned how to dance. He may be healthy and has potential, but he hasn't learned (perhaps he is only five years old). 他不可以跳舞 emphasizes that he doesn't have the permission to dance. Maybe he broke some rules and his parents punish him by not allowing him to dance, so he is not allowed (不可以) to dance. 不可以 (similar to "not allowed") often implies that he knows how to dance. There is also a scenario where the person is not able to dance because of physical constraints (sick or handcuffed or something). This is not included in the 不会 and 不可以 scenarios.
I would say 他没办法跳舞, which roughly translates as "he cannot manage to dance". I can also say 他没办法五分钟内完成这项工作 he can't manage to finish this task in five minutes. Basically there are some objective restraints which prevent him from performing the task, but in theory he knows how to do it.
Does everybody use the Typing thing? I see a lot of people complaining about sentences that should be accepted. I am not trying to be rude or anything but it is getting annoying with everybody complaining about which sentences are incorrect when they should be correct. Duo just wants you to know what the sentence means by letting you choose the right words. Duo just uses simple words and simple sentences so you can understand what it is talking about, even if that means that there are mistakes (English wise). There are a lot of other ways to say this sentence but Duo doesn't care, just say the most simple way of saying it and it might get marked correct. It would be annoying trying to add sentences to deal with all of the complaints. As long as you know what the words and sentence mean, you are all good to go. There's no point complaining or reporting all of these things when all you need to do is know and understand what it means.
Asking about alternative translations is more than just complaining, it's a part of active learning to dig deeper than the often simple or sometimes outright bizzare translations Duo uses. It's a great way to draw in native or advanced speakers and learn new things not covered in the course too. :)
Is it really necessary to complain in the comment section about sentences that need accepting? Seriously, I think it's better to keep things simple and understandable instead of complex and complicated. I think the discussion/comment section about sentences should have comments that talk about how it could be translated differently or if there are mistakes, not a bunch of comments complaining about what should be accepted or not. Going more deeper into the sentence wouldn't make you learn anything, it will just show you another way of saying that sentence. But maybe you might learn a few NEW Words in the English (or your native language) Dictionary. I say you keep things simple, keep it short, no need for complex or extra-unneeded words, then you might get it marked correct.
I really am with you in this! After an exercise, I always go to the comment section to see if there is other translation or maybe an extra grammar explanation. It's ok to feel frustrated if a question is marked wrong and it shouldn't. We, as a community, should be helping Duo to grow as a more complete (and correct) app. But spamming the comment section with complaints is not the right way to do it.
They aren't complaining about a word that was never introduced before into a lesson before this one, they are complaining that they are getting marked wrong when they have to use a specific word and are confused when there is a homophone with a very similar meaning. 他 and 她 are homophones, pronounced as ta1, however 他 means he and 她 means she. This isn't complex at all, however since they are homophones, without the context of the situation, it is impossible to tell them apart. Also, learning a language is supposed to be simple in the beginning. As one progresses in the language, they should enter more complex words and phrases. If you only stick to the simple stuff, you will never get anywhere and will never understand the natives. Natives don't use simple phrasing. People also ask here if an answer should be excepted or not to understand why it isn't accepted, like for the fact that 会 is used for the future tense, however it actually means to be able to, which in English conjugation becomes can, and only through natives' understanding and the metamorphosis of the language can we truly understand why one answer is excepted or the other for the translations. Language is too complicated to stick to simplicity.