learning - Is Japanese that lacks proofreading likely to contain bad spelling or grammar?

Regarding written English that isn't proofread ... it's quality definately leaves alot to be desired. I would advise people against treating written English that wasn't professionally written (for example, mailing lists or Stack Overflow questions) as good English.

Am I likely to pick up bad spelling or grammar from Japanese that is written by native speakers but isn't professionally written?

Assume that I'm reading somewhat serious material, such as the ruby-dev mailing list, rather than YouTube comments.

I'm not really planning on learning spelling and grammar from them, just practicing reading the kana within the emails, but I don't want to mis-train myself (learn something that isn't correct) by accident.

I've also heard warnings not to learn from Japanese done by the opposite sex - sadly, I don't think there'd be too large a risk of that with a programming mailing list!

Answer

Even the quality of professional writings (probably without proofreading) such as an article in an online newspaper is very bad these days. For example, on articles on an online news site www.livedoor.com, which I regularly read, I usually find several grammatical mistakes each day. You can only trust professional writings that are printed on paper.

I don't think it is a good idea in general to learn a language from sources such as programmers' questions, but there are some points that may help you.

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  If something is just a simple mistake, then that should happen randomly, so the more you read, the more likely that that mistake that you wrongly picked up will be corrected. If it happens repeatedly, then that might be slang, or at least you are making the same kind of mistake as natives.

  
  


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  One common mistake you encounter on the internet is 誤変換 'misconversion'. Nowadays, in most cases, the kanji (Chinese character) parts of Japanese are not directly typed on a computer, but are input indirectly: First they are input by their reading, most often by hiragana, and then the user looks through the possible combinations of kanji matching the reading that the computer provides, and picks one. Sloppy people or people with a low education level often pick up the wrong one. For example, I often see 確立 where 確率 is supposed to be used. If you think that a word does not make sense in the context, you can suspect that it is meant to be a different kanji word with the same reading.

  
  


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  Another common mistake is the wrong use of particles. But they are not that frequent, and you will likely notice it when it is wrong if you read enough.