Free self-study guide starting with a phonetic course, then graded grammar and quizzes.
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Structured like an actual introductory syllabus: an introductory phonetics and alphabet course first, then grammar lessons with audio, interactive exercises and immediate-feedback quizzes. That ordering matters in Russian, where getting the sound-to-letter mapping wrong early is expensive to undo. All free. It stops well short of intermediate and the site looks dated, but nothing else free covers the first steps this carefully.