Anki is a powerful, open-source flashcard program renowned for its effective spaced repetition system (SRS). It isn't a language course itself, but a highly effective tool for memorizing vocabulary, phrases, or grammar rules that you input yourself or download from shared user-created decks. Its high degree of customization allows for rich cards with audio, images, and cloze deletions. While its interface can be unintuitive for new users, its effectiveness for long-term retention is largely considered unparalleled for dedicated learners.

The Paul Noble Method is a purely audio-based course designed to get you speaking quickly and without stress. It avoids rote memorization, instead teaching you how to build sentences using a small set of high-frequency words and simple grammar rules. This approach is highly effective for developing foundational conversational skills and can be used passively, such as during a commute. Its primary limitation is the complete absence of reading or writing practice, and it is intended to build a core competency rather than advanced fluency.