That pesky German language and the quirks of the human mind
After close to 14 years in Germany, I should be able to write correct German (barring the odd slip of the keyboard that we all make even in our native languages). Reality, alas, does not quite agree: I know most of the rules as well as the natives, and with enough proof-reading I can reach a near-native level, differing mostly in that my style, choice of words, whatnot, can be strongly influenced by Swedish and English. However, the extensive proof-reading is absolutely necessary: My first drafts tends to contain errors at several times the rate of my English or Swedish writings, because the “text generating” part of my mind makes many unthinking choices that are simply incorrect—even when the “text reading” part of my mind knows that they are incorrect… For instance, reading the notification email for a comment I sent earlier today, I found that I made a back-reference to a woman with the masculine “der” instead of the feminine “die”—a blindingly obvious error to any semi-proficient reader. A particular common error of mine is using a dative or accusative in constructs where a nominative is called for, e.g. “X is Y”. (The two former cover the English objective case, while the latter is the subjective.) Presumably, the presence of a verb toggles an internal “objective” switch irrespective of what verb is used.
This is a particular nuisance when I comment on German blogs: If I do not proof-read several times, there will usually be at least one error of the “a ten year old should know better” kind; if I do, the effort of submitting a comment grows to be several times what it is in Swedish or English.