The purpose of this study is to analyze the current status of Korean adults’ speaking ability of the Korean language and compare it with results from 2013, based on the findings of “The 2018 National Assessment of Korean Language Ability (NAKLA),” to determine academic and educational implications. This study examined the speaking ability of 2,939 people aged 20 to 69 years, sampled by probabilities proportional to size. The level of speaking ability was analyzed based on variables such as age group, gender, district size, occupation, level of education, major, reading amount, and internet usage. The analysis of differences by demographic characteristics found statistically significant differences in the variables of gender, age, occupation, and level of education, but not in district size. Furthermore, an analysis by background variable found statistically significant differences in the variables of reading amount and internet usage, but not in major. The study was meaningful as 2,939 adults in Korea were selected using a “sampling with probabilities proportional to size” method to directly evaluate their speaking ability. The implementation of the assessment and grading can contribute to basic data at both educational and policy levels as a wide variety of group variables has been established on a national scale to identify differences between the groups.