Brazilian Portuguese has so many unique concepts like Ranço - that inexplicable feeling of disliking someone without a proper logical reason -, Arretado - (adj) awesome, skillful, intrepid, angry -, or Fogo no rabo/cu - roughly translated to "fire in the ass", it means getting really excited -.
You can learn Brazilian Portuguese online on Qlango, Mango Languages, or Lingvist.
Learn Brazilian Portuguese on Lingvist
Lingvist is a good app for anyone who is busy but wants to quickly learn a new language. The app focuses on around 5000 words in each language to help you learn at an accelerated pace, the theory behind it is that these words are all that you need. Since its inception in 2014, it has been downloaded by over 6 million people.
Other languages: English, Estonian, French, German, Ling, Russian, or Spanish
Learn Brazilian Portuguese on Mango Languages
Mango Languages uses algorithms to offer a personalized language learning experience. Language learners can speak and hear the language they are learning, participate in daily quizzes to reinforce their progress, and even engage in live conversations with native speakers around the world. Language instructors also use Mango Languages to create customizable lessons tailored to each student's current skill level.
Qlango is a language learning app that promises to help you learn a new language in 5-minute increments, as each lesson lasts that long. It offers quick and easy lessons, along with interactive games, flashcards, and chatbots to help you learn vocabulary and grammar.