This thesis aimed to research ‘Language Awareness’ in Korean documents of the middle ages. For this purpose, the thesis found texts including the word ‘言語’ in Annals of the Joseon Dynasty, investigated the meaning of the word ‘言語’ and contexts used the word. The word indicated the spoken language. The word that was united new words, for example the written language, behavior, practice and so on, expanded limits of its meaning. This shows that the interest in the middle ages would be not ‘what the language is’ but ‘what the language do’. This language awareness was connected with language norms and language manners. So this thesis analyzed a party of <言語>«사소절(士小節)», which was a book about language norms and language manners in the later eighteenth century. The contents of a party of <言語>«사소절(士小節)»was language manners in the situation of communication by a spoken language, especially how to be considerate of others.. The result shows that a high official class in the middle ages thought that words was very important for the good relations with others. So language awareness in the middle ages was how to use words properly in the context of communication and to keep language norms and language manners.