You can change display language and native language in eJOY English App.
(Display language: Your app is displayed in this language. Native language: Word’s meaning, Auto-translate subtitles and other subtitles are automatically displayed in this language.)
To change them, go to More (1), then Setting (2).
Then, go to Learning Settings.
Choose your preferred language(s) in Native Language and Display Language.
After making changes, hit the arrow button on the top left of your screen to apply the changes and go back to the app.