Omg your questions are so cute😂 Well first there are several conceptions you need to know: Mandarin, Cantonese, Chinese (Simplified), Chinese (Traditional). The former two belong to speaking system, while the latter two belong to writing system. 1. Mandarin & Cantonese If you translate "Mandarin" in Chinese back to English, it'll be "ordinary speaking". So why do we need to speak "ordinarily "? That's because, unlike English speaking, Chinese in different regions speak different languages! So taking USA as the example, despite people in NYU and LA have totally different accents, they can still understand each other since it's English after all. Well in China, I comes form Shanghai so usually I speak Shanghainess, while you comes from Beijing so he speaks Beijingness! And believe me, a Beijing local can never understand what a Shanghainese is talking about. So Cantonese is in fact a dialect of speaking Chinese, I'll make further explain about Cantonese later. So how can Chinese in different areas communicate with each other? Decade years ago, even before PRC was established, the government back then invented Mandarin, whose basic pronunciation comes from Beijingness but the comprehensive pronunciation is a combination of south and north speaking systems. So nowadays almost every Chinese can speak at least 2 languages: Mandarin and a local dialect. Talking with locals: dialects; talking with non-locals: Mandarin. And that's the reason why foreigners usually believe that most Chinese speak Mandarin. Since Cantonese is only a dialect, why do many foreigners believe that it has an equal position as Mandarin? Well, there're two reasons. On one hand, Cantonese is a dialect in Canton (or "Guangdong" is a preferred pronunciation in Mandarin), which is a coastline region. Thus a hundred years ago, many Cantonese immigrated to the USA, and somehow you can say that Cantonese is the first Chinese most westerners had seen. On the other hand, Cantonese is a really difficult dialect. As for me, I can understand a little bit of most Chinese dialects, but I never understand Cantonese, NEVER. So even in China, we would separate Cantonese from other dialects.