I took a couple of semesters of Spanish in school, but not enough to be able to do much with it. I've found Duolingo to be very effective for helping build up vocabulary, and even for learning grammar rules. A couple of things I've found to be very helpful:
- Each lesson has a guide that shows what's new. This is a bit hard to find on the website (click on the lightbulb above the "Practice" button for any lesson), and (last I checked) isn't available at all on mobile.
- There's a discussion board associated with each sentence. This can be immensely helpful for getting tips from more experienced speakers regarding various tricky aspects of the language.
Is it enough to build fluency by itself? Doubtful. But I find it very helpful for building vocab with a ~20-minute daily investment.
- Each lesson has a guide that shows what's new. This is a bit hard to find on the website (click on the lightbulb above the "Practice" button for any lesson), and (last I checked) isn't available at all on mobile.
- There's a discussion board associated with each sentence. This can be immensely helpful for getting tips from more experienced speakers regarding various tricky aspects of the language.
Is it enough to build fluency by itself? Doubtful. But I find it very helpful for building vocab with a ~20-minute daily investment.