Yes! I've had this _exact_ thought while reading "Sell Like Crazy". Such a badly written book in this sense. Tons of ideas and methods but it doesn't truly stick in my mind if everything is ELI5'd to infinity. I'd rather read fiction (e.g. Murakami) where I have to close the book and think before I continue.
> You need to know about 20,000 words in any language to sound fluent
Are you sure about this? AFAIK the use of words in a language isn't distributed evenly, but according to a Pareto distribution. Thus, you can speak _okay_ knowing only ~500 words, I believe. It won't sound perfect but you'll speak and understand pretty decently.
I once wrote a python script which read words from a .txt file full of french words with their english counterparts and then displayed the french word, waiting for you to type your guess. It gave instant feedback which I thought important for learning anything. The file contained the 500 most used french words according to large book surveys.
This was in my last year of school and it saved me during tests where I had to write coherent sentences in french.
