First of all, I think what you said should be broken down into parts. If you're in a purely English-speaking environment and spend a long time working on it, reaching a conversational level is definitely achievable. Take my dad's younger brother, for example. He only had an elementary school education and immigrated to the U.S. at the age of 50. He couldn't even recognize all the English letters back then. Now, after almost 20 years in the U.S., he can manage basic communication. Of course, it's more like throwing out individual words, and his listening is much better than his speaking. Why is it still not great? Mainly because, even though he's in the U.S., he has always communicated and interacted with Chinese friends. Naturally, his English progress has been slow. He only remembers some English when he has to use it, like when shopping or eating out. But if you're in a purely English-speaking environment and actively learning, you can definitely improve naturally. For example, my aunt's child went to the U.S. for graduate school after finishing college. Their English wasn't great during university—they didn't even pass the CET-4 exam. But they studied nursing in the U.S., which is almost as demanding as studying to be a doctor. After about two or three years, their English level was nearly native. Now they've been in the U.S. for 15 years and are completely fluent, like a native speaker. So, you're absolutely right—working hard is essential to learning English well. But the environment does make a difference. The more you're immersed in a purely English-speaking environment, the more it helps.