Langtern English app for iPhone and iPad

Langtern is the English language app for students and teachers:

Student: helps you learn English by assisting you when navigating English web pages, watching videos in English, or reading ebooks/PDFs in English. These functionalities are completely free, although there are other advanced student functionalities under a small subscription, like online content search by difficulty level.

Teacher: makes it easy to create exercises automatically from online material with artificial intelligence. Your students can do their exercises interactively through the app. These functionalities are available under a subscription.

The terms of service can be found at: https://langtern.com/public/doc/en/tos.html