Why can't Johnny can't write good?
Not necessarily vocabulary, or simple grammatical mistakes like the above. It's because he can't use simple conjunctions. Teachers at a Staten Island school changed the game by teaching them how to write... and as a result, how to think.
What words, Scharff asked, did kids who wrote solid paragraphs use that the poor writers didn’t? Good essay writers, the history teacher noted, used coordinating conjunctions to link and expand on simple ideas—words like for, and, nor, but, or, yet, andso. Another teacher devised a quick quiz that required students to use those conjunctions. To the astonishment of the staff, she reported that a sizable group of students could not use those simple words effectively. The harder they looked, the teachers began to realize, the harder it was to determine whether the students were smart or not—the tools they had to express their thoughts were so limited that such a judgment was nearly impossible.
Being able to express complex thoughts in language is the first step towards thinking in meaningful ways. When I first started at YC, I was astonished at how tough it was to understand what people were doing. I assumed that most founders had some specific concept in their head and they were merely struggling to find words to express them. PG set me straight though -- if a founder can't express their ideas clearly to others, then the simplest and likeliest explanation is actually that the idea is not particularly clear to them either.