I have the same problem as yours. I hope there will be some ways to deal with it, but it's an unfortunately unlikely case. Maybe the saying is commonplace but true: use more English; practice makes perfect.

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You can double your vocabulary learning speed by learning words in pairs. When you learn a new word, try to find its antonym (opposite) or its synonym (same or similar meaning word; check out a Thesaurus) or some connection type word. If you learn words in pairs the vocabulary learning process becomes alot faster. 在对学习的话，您可以双击你的词汇学习的速度。当你学会了一个新词，试图找出其反义词（对面）或它的同义词（相同或类似含义的词;！检查词库）或某些连接类型字。 如果你在对学习单词词汇学习过程变得快了很多。 I learned this method of increasing your vocabulary from a teacher on italki named Johnz and I have found it to be very useful.

What do you mean by rapidly? 3,6 months, a year? What really matters is to find out what your objectives are (listening, writing, speaking) and develop a study plan (how many hours you will dedicate per day to reach those objectives). Anyway, If you want to go fast, don't waste your time. Here are some suggestions: whenever you are browsing the internet, give preference to the English sites; watch films without subtitles; chat rooms. Those are one of the things you can do in your spare time. Good luck!

这也是我的死穴，但除了死记硬背，应该没有其他办法了