Matchering - Open-source audio mastering app that masters music based on any reference track you provide.

Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.

eMastered - eMastered makes a song sound better through online mastering.

Mondly - Learn 33 languages in 500 bite-size lessons and 14 conversational modules.

Audio Mastering - Pro quality, fully functional audio mastering application for iPad.

Lingvist - Lingvist helps you take your foreign language skills to the next level with a broad selection of exercises and lessons.