Learn Mandarin on Rosetta Stone

Rosetta Stone is a language-learning app that started in the 90s for auditory learners.
Price: Free
Devices: Android, Apple Watch, iPad, iPhone, and Web

Learn Mandarin on Awabe

Awabe is a flashcard language learning app on Android. It focuses on vocabulary, offering as much as 4,000 words for each language.
Price: Free
Devices: Android, iPad, and iPhone

Learn Mandarin on LingQ

LingQ is a language learning app that uses the same logic for learning a new language as learning your native tongue: using content you already like. They have books, news, podcasts, sports coverage, politics, culture, and food to name a few.
Price: Free
Devices: Android, iPad, iPhone, and Web

Learn Mandarin on LuvLingua

LuvLingua is a language learning app that uses an interface that is more geared towards a younger audience. It's focused on vocabulary learning and listening skills. The basic app is free but the more advanced ones are paid.
Price: Free
Devices: Android, iPad, iPhone, and Web