also, dialects of a certain language can sometimes be mutually unintelligible. chinese, for example, has hundreds of different dialects, and many native speakers of those dialects cannot understand each other without knowing the other's dialect. for example, the local dialects of beijing, shanghai, and hong kong are mandarin, shanghainese/wu chinese, and cantonese/yue in that same order. if natives from each of these cities were to talk to each other in their native dialects, they would not understand each other. this is because they are too different from each other. this is why the governments of china and taiwan want their citizens to speak standard mandarin in public so that there can be a spoken dialect of chinese everyone can understand. while the spoken dialects are mutually unintelligible, they all use the same written code, chinese characters, so they can understand each other if they write to each other.