a few days now, the application bought seconds is completely in Japanese and no you can change the language, I do not refer to the spoken language but to the interface. Even if you re-download the application, the problem does not resolve. the application is unusable.
Seconds uses the first preferred language, you have set up for the device, that it has a localisation for.
You can find these settings in the device Settings app, under General->Language & Region. Move your preferred language to the top of the list.
The app is available in English, German, French, Spanish, Swedish, Russian, Japanese, Portuguese and Chinese.