The study analyzes the semantic differences between the English verbs of near-synonyms extend and expand through corpus linguistics and a survey. Using COCA, COHA, and the Merriam-Webster dictionary, the study compares authentic language data and dictionary definitions. The results show that there are differences in the frequency and usage trends of extend and expand in the corpora. Students had difficulty distinguishing their meanings, which was reflected in low comprehension and accuracy rates in the survey. The analysis of noun collocations also reveals differences, with some collocations appearing in unexpected ways. This suggests limitations in vocabulary learning and understanding of these words in the context of learning English as a foreign language for Korean college students, where exposure to natural English language environments is limited. The study highlights the importance of providing students with authentic language experiences, diverse contexts, and the use of dictionaries to improve their understanding and use of extend and expand.