[cranks]

The whole point of "learning" a language to me is to become being able to use it in real life situations, so even if your German is fraught with errors, you are done with "learning" once you have a good enough command of the language to function as an adult, i.e. work, in an all German environment, imo. After that, you just have to use it as much as possible, and do what native speakers do, like taking a writing class and/or a speech class.

Both in learning German and learning Japanese, I'm sure classes help to a certain extent. But German seems close enough to English that you can understand most of what a material for adults, for example a TV news show or an article from a paper, is saying by just replacing all the words with English ones. With Japanese though, you'll have no idea if you do the same. You can probably get around it by reading grammar books and doing text books on your own too, but getting to the level where you can somewhat understand basic Japanese materials would take hundreds of hours of study, so it seems to me you kind have to be really passionate or/and dogged. I feel like I can learn German or Spanish all on my own, but if I were to learn a language like Arabic, I'd take some classes. I can probably self-teach Arabic too, but it seems like too much work.

Whatever you do, expect to spend 4 times more time on Japanese than German to get to a certain skill level. It'll probably take 1000 hours to acquire basic skills like asking directions and talking about the weather, 3000 to 4000 for business level skills, over 10,000 to be native like. How you go about it probably does't matter that much at the end of the day.