The appearance of the new things will definitely cause the disappearance of the old things because it is the basic regularity of things develop that the new superseding the old. Of course, the vocabulary is not an exception. Contrast with the new words, overseas students who study in Mandarin learning courses should know that the so-called old words are the words existed in the vocabulary in the past but no longer used in today’s life.

The old words are the words that ever appeared in Chinese language. However, with the development of society, they are no longer used by people in modern time. In fact, there are two forms of expression that the old words disappeared. Firstly, in order to meet the needs of standardization of language, people weed out some words artificially. For examples, 绍介 was standardized into 介绍 , 味素 into 味精 ， 游学生 into 留学生 , etc.

Another condition is that the things, phenomena and notions that the original expressed no longer existed in modern society. As a result, the words also died out gradually. When you study in intensive Mandarin course in China, teachers would tell you that those words have lost the value of symbols, thus losing the meaning of existence. Then, they are sifted out by the vocabulary system. For some examples, the words太尉、国子监、须臾and丫环only existed in ancient China. Therefore, they are useless in modern society but only in some history books.

Different periods of times have different new things, making it the different words to express them. For example, those words such as红卫兵、生产队and上山下乡were very popular in old China. However, the disappearance of the old words is a long and gradual process, not so rapid like the appearance of the new words.

When you attend to school in Kunming to study Chinese, teachers may tell you that the words might revive during the process of dying out. Some words are stepping to disappearance, but they come into alive again in modern society such as 旗袍、股票、保镖. The disappearance of the old words an expression form that the society chooses language.