What Actually Works
The language learning community is defined by a central debate that colors nearly every recommendation online:
Stephen Krashen's View
We acquire language subconsciously through exposure to material we can mostly understand ("i+1"). Conscious grammar study only produces a surface-level "monitor". Real fluency comes from meaningful input, not memorization.
Dreaming Spanish · AJATT · Refold · LingQ
The Opposition
Explicit grammar instruction, output practice, and error correction are necessary for precision and fluency, especially for adults who learn differently than children.
FSI / DLI · Assimil · Pimsleur · Michel Thomas
Where the Community Lands
Most successful self-learners settle somewhere between the extremes. Reddit's r/languagelearning broadly agrees:
Plateau at around A2. Functional survival phrases but nowhere near real comprehension.
They work extremely well, but require enormous time investment and discipline that most people can't sustain.