Learn English 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
English has so many unique concepts like headcanon (ideas about a fictional work that individual fans have come up with and accept as true for themselves without the official authors necessarily supporting (or denying) them), Halcyon (adj.) (denotes a period of time in the past that was idyllically happy and peaceful), or mag dump (shooting an entire firearm magazine onto a single target).
You can learn English online on Mondly, Duolingo, Babbel, Busuu, Lirica, Drops, Pimsleur, Rosetta Stone, FluentU, or Lingodeer.