The present study investigates Korean learners’ use of English lexical verb forms and identifies learner deviations from native usage patterns. It examines the frequencies of six verb forms (i.e., base, present, third-person singular, past, gerund, and past participle) in a native and a learner corpus of argumentative speeches. The study reveals that certain verb forms are overor underused by Korean learners of L2 English, compared to native speakers of English. It is also found that L2 overuse and underuse of verb forms are closely related to Korean learners’ overreliance on or avoidance of major lexico-grammatical patterns around the verb forms (e.g., to + base verb). These findings have pedagogical implications for teaching Korean learners to use various verb forms with major lexico-grammatical patterns in English speaking.