As an English teacher, one of the most common problems I've found with my students is their lack of confidence with speaking, and difficulty in understanding native speakers. Another problem could be that a foreign language taught in schools can sound quite different to what native speakers actually use. There are a few English words and expressions that I'd never heard until I came to China. The most common one in my experience is "How are you? I'm fine, thank you, and you?" I appreciate that although this greeting is much too formal for everyday use - it's easy to learn and helps build confidence. However, it can be a hard habit to break. I've seen many parents correct their kids if they don't use that exact phrase, as if simply replying "I'm fine" would somehow be rude. In fact I'm banning my students from saying that in the classroom, insisting a simple "I'm fine, thanks" is good enough. "Seldom" is another one that I find interesting. The first time a student told me "I seldom watch TV", my initial reaction was a stupefied look, followed by "Huh?" I then realized the student used "seldom" when it's more common for us to use "rarely." I was just as confused when I first heard a toilet referred to as a WC (water closet), another English term I'd never heard of back in Australia. Of course, my students know the other names for it like bathroom, toilet, washroom etc. so to prefer that name is an interesting choice.   I don't mind that my students have substituted familiar English words with their own, far from it. It reminds me how creative they can be with not only their language, but with mine as well. It's healthy for English to evolve   and change and I'm happy to add these new words to my vocabulary. One important lesson I've learnt is that textbooks can only help you so much. For further improvement you'd better practice with native speakers. What does the article mainly tell about?
Learning English needs confidence. Native speakers are hard to understand. Chinese-English has something different. Chinese students are more creative.