If you have read any of my books, you will probably not be shocked to discover I'm a language geek (the kind that gets a degree in linguistics and stops conversations to analyse sounds and etymologies), reading is my first love, though, so naturally learning languages by reading in a foreign language is two great things that go great together! I find Kindle and other apps that allow you to look up words to be okay but nowhere near as good as an actual literary translation, which is why I have aligned a lot of my books side-by-side. There's mainly English, German, French and Italian combined with each other but I got a couple Portuguese and Spanish too.
I hope this helps you too in your language journey! If you have any ideas, please write to me
If you need some recommendations for language learning resources, here are my favourites:
Duolingo (Besides grammar lessons based on translations, they have little stories you can follow to make it more interesting--as a plus, they're pretty inclusive representation wise <3)
Sounter (Karaoke for language learners, with exercises)
Drops (Only 5 minutes a day are free, but it's a very visual system that works great for basic vocabulary)
For writers, here's my take on including foreign languages in books.