I am a bilingual high school teacher. I mostly read non-fiction, especially history, but I am also a sucker for science-fiction and fantasy novels.
I really like the Pimsleur language learning products. As a French teacher myself, I know the work it took to master another language and what techniques work to help students build skills. They are absolutely right when they say that it is about functional sentences useful in real situations. It is also about oral skills, not written grammar tests. I like that they also don't just have you repeat - they explain what each part of a phrase means as well, which allows you to adjust the sentence accordingly with other vocabulary. For example, they teach you "Are you American?" "Yes, I am American." I am Canadian. I looked up the word for "Canadian" and could practice the sentence that I would use on my own ("Are you American?" "No, I am Canadian.") knowing that the structure was correct. It also helped to hear two different speakers, one male and one female, to make it easier for me to pronounce things correctly. A 30-minute lesson is enough to absorb at one time - you need to really think to keep track and you might need to do it twice, but it isn't too intense.
Note that the free download is just for the first lesson, about 30 minutes. On Audible they have Phase 1 units 1-30 split by 1-5, 6-10, etc. for one credit each or as 1-30 for 5 credits. Same deal with the more advanced Phases 2 and 3. Don't expect a full 30 lessons for free! But this is a great way to see if you like the way the lessons work and if you want to learn more of this particular language.