This study aims to construct a corpus of 17th-century Korean personal letters, classifying them into royal and aristocratic (yangban) correspondences, and to compare their linguistic features through quantitative analysis. Based on a total of 285 letters—including ｢현풍곽씨언간｣, ｢숙명신한첩｣, ｢숙휘신한첩｣—the 17th Century Eongan Corpus was developed with detailed morphological analysis and lemmatization. The findings reveal that yangban letters tend to utilize practical and colloquial expressions, whereas royal letters demonstrate a more written style with enhanced forms of greeting and ritual politeness. Distinct differences were observed in pronoun usage, speech levels, sentence endings, and adjectives. Furthermore, phonological changes and dialectal vocabulary appeared more frequently in yangban letters, whereas royal letters maintained linguistic conservatism. This study contributes a new methodological approach to the field of historical Korean linguistics by providing a structured corpus and employing corpus-based analysis to elucidate stratified stylistic features.

「Hyeonpung Gwakssi Eongan」 (A collection of Korean letters)is of 176 letters. Of 176 letters, 83 letters are about dietary which are 47.16% of the total letters. In 83 letters of dietary, there are records of rice, glutinous rice, barley and buckwheat, and also yeast, malt, flour, wheat bran. For poultry and meats, there are beef, raw & dried pheasant, chicken, quail and other birds. For fish and shellfish, there are sea fish such as cod, herring, croaker, flatfish, and freshwater fish such as crucian carp. For main dish, there are cooked rice, porridge, noodles and dumplings. For side dish, there are soup, grilled dish, nureumi, stir-fried dish, steamed dish, fermented fish, raw fish, jaban and chimchae. For rice cake, there are ancestral rites cake, sanseung, gyeongdan, ssookddeok. In「Hyeonpung Gwakssi Eongan」, Ju Gwak instructed food preparation, grocery shopping, recipe, guest-welcoming, housekeeping, making bed, transportation, curfew for his kids and clothing for his wife one by one. Furthermore, there are records of dietary lifestyle of spring season and the month of November in lunar calendar. Lastly, there are birthday ceremony, coming of age ceremony, wedding ceremony, funeral ceremony and ancestral rites ceremony according to Confucianism ideal and their food recipe.