This study explored generational differences in acceptance and use of AI-based language learning technologies among pre-service GenZ and in-service GenX&Y English teachers in Korean EFL (English as a Foreign Language) context. As AI tools like machine translators and ChatGPT become more prevalent in classrooms, understanding how different generational groups perceive and adopt these technologies is crucial for their successful integration. Using a mixed-methods approach with 70 participants, the study analyzed both quantitative and qualitative data. Results indicate that GenZ pre-service teachers are more open to adopting generative AI technologies, recognizing their potential to facilitate personalized learning tailored to individual student needs. However, their enthusiasm was accompanied by concerns about administrative challenges, particularly in managing AI-related tasks. In contrast, GenX&Y in-service teachers showed a more cautious approach, preferring traditional non-generative AI tools such as online translators and grammar-checking applications. They primarily regard AI as a supplementary tool to enhance existing teaching practices, with limited interest in its use for core instructional tasks. Instead, they emphasized its role in post-class tasks, such as grading, assignment management, and providing prompt feedback. These findings highlight the importance of designing generation-specific teacher training programs that address the distinct needs and challenges of each group.