Lingedia: Learn English is a free Android app developed by Language Learning Systems. The app is designed to help users learn English vocabulary using the spaced repetition method. With Lingedia, users can improve their vocabulary by creating a personal word list, taking quizzes, and listening to pronunciation in three dialects (US, UK, AU). The app also features free offline dictionaries, translation between English and over 100 other languages, and daily news articles from the BBC.

The app's spaced repetition algorithm determines the best repetition time for each word based on how well users answer it. This method ensures that users memorize new words and avoid forgetting them. Lingedia also includes a vocabulary size test that estimates how many English words users know, and a progress indicator for each word that automatically moves to the "learned words" list after reaching 100%.

Overall, Lingedia: Learn English is an excellent app for anyone looking to improve their English vocabulary. It is perfect for students preparing for exams like TOEFL, IELTS, GMAT, ACT, MCAT, SAT, GRE, and more. The app is easy to use, with a user-friendly interface, and is available offline, allowing users to study anytime, anywhere.