영단어 완전학습 - 사전 단어장 Free is an educational app designed for elementary, middle, and high school students, as well as TOEIC test takers. With a total of 12,811 essential vocabulary words, this app utilizes brain science theories to provide efficient memorization and thorough review systems.

The app incorporates a spaced repetition system that shows unfamiliar words more frequently and familiar words less often, ensuring optimal retention. It also applies the dual coding theory, presenting both linguistic and visual information to enhance memory recall. Animated images are included to increase immersion and engagement.

In addition to traditional learning methods, the app offers quiz-style tests to improve memory retention and make learning more enjoyable. Automatic reminders for review sessions are also provided to ensure timely and consistent practice.

Please note that changing the TTS voice can be done through the iPhone's settings.

Overall, 영단어 완전학습 - 사전 단어장 Free is a comprehensive and efficient tool for mastering essential vocabulary words. It combines scientific learning techniques with interactive features to create an engaging learning experience.