My target language is less challenging than Chinese, but my experience is that it takes more repetitions and more use to create words that I can comfortably speak and use in conversation (active vocabulary) than words that I can recognize when I hear them or see them (passive vocabulary.)  I think adding 20 passive vocabulary words a day is reasonable.  However, those words usually need to be seen and heard repeatedly and used, at least in my mind if not with a teacher or partner, before they become more than ¨on the tip of my tongue.¨ I think it is very hard to guess how many words a day I convert from passive vocabulary to active vocabulary, but it feels like a much slower process.  Fortunately, when I think of the difference in my native language between how many words I recognize and how many I actually use on a routine basis, I am reassured that my active vocabulary does not NEED to be nearly as big as my passive vocabulary.  I read a lot of books and watch a lot of movies, so there is just no way to estimate the rate at which the repetition becomes enough that they are so familiar to me that I use them easily.  I think I have to learn them really well and then also ¨get my mouth around them¨ actually using them awkwardly and tentatively a few times become they become at all natural and easy for me to use.