I find Anki is useful for boosting the frequency of important but medium-frequency words/phrases. This is where language learning usually plateaus. Assuming on

I find Anki is useful for boosting the frequency of important but medium-frequency words/phrases. This is where language learning usually plateaus. Assuming one is being constantly exposed to comprehensible input, the first 80% (by Pareto principle) is usually easy because they're high frequency patterns and the brain automatically picks up on what to pay attention to and tries to retain them. (pattern/word frequency) But then there's the 10% of high-leverage phrases that native speakers use (which makes them sound native) but not quite often enough for our brains to pattern match. These are the hardest to retain because it's diminishing returns for our brains. (weak signals in training data) This is where Anki helps: the SRS artificially boosts the signals for these phrases. (synthetic data) I also use Anki for easy confused words/phrases -- in Portuguese, "rodoviária" (bus station) and "rodovia" (highway) are easily confused, but Anki's SRS prompts me to differentiate them. (discriminative learning)