If anyone's planning on learning Japanese with Duolingo: don't. Did that for a few weeks, basically learnt nothing. I soon found out from experienced learners that it was terrible [0]. I then discovered the AJATT/MIA[1] methods of learning Japanese, which prioritize immersion/sentence mining of the target language and learning vocab/kanji and sentence structure through Anki decks (you can use any SRS system but Anki is by far the best with a rich ecosystem of Japanese integrations such as the Yomichan dictionary).

I used the foss app Kakugo (available on Fdroid, not sure about the play store) to learn the hiragana and katakana writing scripts in 3 or 4 days, and have now moved on to reading Tae Kim's Grammar Guide[2] for learning grammar and using Refold JP1K[3][4] style anki decks to learn my first 1000 kanji.

However this method is more of a 'grind', you need to set aside at least 2 hours a day so that you can read Tae's textbook, learn new vocab and do your reviews through Anki. In your free time, once you have a decent amount of grammar understanding and vocab, you need to be immersing in Japanese, so anime, J-dramas, etc. (Jap music isn't very helpful here).

[0] Review of Duolingo Japanese course from a 2+ year user of Anki/immersion based learning: https://youtu.be/jf-SbSfiXn4 [1] The AJATT method has been around for a long time, it means All Japanese All The Time. It basically promoted SRS and immersion based learning. MIA is basically the same thing, mass immersion, started mainly by MattVsJapan. However I use the guides and tools created by AJATT-Tools, whos contributors focus on tools for Linux, such as MPV scripts for sentence mining (creating Anki cards with unknown vocabulary semi automatically while watching subtitled content, with audio and visual cues). Their guide builds on top of MIA and AJATT style methods: https://github.com/ajatt-tools [2] The defacto grammar guide for Japanese that isn't afraid to teach you Kanji from the start: http://www.guidetojapanese.org/learn/grammar [3] Explanation of the JP1K style Anki deck: https://youtu.be/53qKsYxVhoM [4] Deck system is created by https://refold.la, however I use AJATT-Tools's version of the deck because it includes example sentences (and Kanji have different meanings in context).