This article focused on analysing the original, extended and derivative meanings of ten characters “口kou, ?jin, 含han, 味wei, 呼hu, 吸xi, 吹chui, 吃chi, 名ming, 命ming”, which have common radicals, “口kou” in order to figure out Chinese characters by way of radicals. It also tried to analyze their cultural undertones and impacts of Chinese social changes on them through the sociolinguistic analysis of some of the words. “口部字kou buzi” generally means “specific body parts or actions related with eating or saying.” Chinese people of all ages lay stress on eating, so it was possible to use “口部字kou buzi” as the objects of sociolinguistic research, which profusely reflects Chinese history, society, culture and even their emotions in it. Each word analyzed in this article originally had their individual meanings as the parts of all the Chinese characters in common use, but their meanings were extended or reduced without deviating from the original boundary as the parts of “口部字kou buzi”. Most Chinese characters in these modern times have the inherent meanings in 『說文解字今釋Shuo wen jie zi jin shi』 and new meanings were added, based on the forms and meanings of each character. They usually developed towards referring to abstract concepts from concrete objects. However, some of the characters have been changed into neologism and loanword such as “口香糖kouxiangtang”, “脫口秀tuokouxiu”, “吃秀chixiu” influenced by social development and introduction of foreign cultures. In addition, this study was able to draw cultural undertones through sociolinguistic analysis, based on semantic changes of the words mentioned above. For example, we could make out how the Western way of thinking, Western ideas and culture have extensively changed Chinese society by studying words made up of “口kou”. Words composed of “味wei” showed us the developmental process of 五味wuwei and 中醫zhongyi, which can be called as the result of Chinese traditional culture, and “呼hu” and “吸xi” let us see the aspects of realization of Taoism culture, a Chinese traditional thought. Especially in the case of “吃chi”, we could find the Chinese elements reflected by relatively abundant culture compared with other words, because Chinese people were more concerned with eating in their long history and tradition. Lastly, Chinese naming tradition shown in “名ming” reveals the phases of the times, by letting us compare the values of each period in history. Therefore each Chinese character can be a new standard which shows us the way to another different China in the past and the present, as long as we regard each character as the essence holding cultural symbols and social meanings, not simple marks of textual records.