My ability in German is considered good by native speakers and I have no difficulty in conversation, or in understanding radio and newspapers. Although I had exposure to German in my younger days at home, while working on a German ship and while working on construction in Vienna, I really could not carry on a conversation. In November 1986, I decided to spend the month learning German.
I went to many secondhand bookstores in Vancouver looking for reading books in the German language which had vocabulary lists. I must have bought about ten or fifteen of such books as well as various cassette tape products in German. The readers were full of the scribblings of the people who had used them before. For one month I read and listened to tapes in German, with the help of vocabulary lists. Of course I achieved a dramatic improvement in my German. I was subsequently able to improve on this during visits to Germany. But it was hard work.
In German, the nouns have three genders. Word endings change depending on case. This is very hard to master in speech. Only repetitive listening has enabled me to cope with this difficulty, not explanations and lists. I just speak German the way I hear it and hope for the best. My German is natural and fluent, but I am resigned to the fact that I am not perfect in German grammar.
I never had to pass a test in German, but I have done business in that language. I have also traveled to the wonderful medieval towns of Germany, sat down in restaurants and engaged the locals in lengthy conversations in German. I know that I frequently get my genders and cases wrong. It has not held me back. On the other hand, I know that to improve my grammar I just have to listen and read more, and occasionally refer to grammar texts to reinforce what I am experiencing in the real language. The isolated study of cases and genders, without a lot of language exposure, will not enable me to improve my grammar in real situations.