According to paragraph 3, how did customers help the author learn English?

When I was thirteen, my parents bought a laundromat on the east side of Fort Worth, and for the next five years it was where I did my homework. I sat at the folding table in the back, between the soap machine and the row of dryers, and I learned to write essays over the sound of tumbling towels.

My parents had moved from Vietnam a few years earlier, and their English was still careful and slow. Mine was better, so I became the one who answered questions. A man needed to know which machines could hold a big comforter. A woman wanted to know whether we could make change for a twenty. I explained the same rules so many times that I could have recited them in my sleep.

But the laundromat taught me far more English than it needed from me. Customers waited almost an hour for a wash and dry, and many of them liked to talk. Mrs. Ortega, a retired teacher, corrected my grammar while she folded her husband's shirts. A truck driver named Curtis told me about every state he had driven through, and I found each one on the map taped beside the counter. An older man brought me his crossword puzzles when he got stuck, and I pretended to know the answers until I actually did.

At the time, I was embarrassed. My friends spent their afternoons at practice or at each other's houses, and I spent mine with strangers' socks. I never told anyone at school where I went after the bell.

Now I teach English to newcomers at a high school in Houston. On the first day of every school year, I tell my students that a classroom is only one place to learn a language. Then I tell them about the laundromat.