Pimsleur Essential Russian is divided into 3 levels with each made up of 30 lessons lasting approximately 30 minutes each. By the completion of the course a learner is taken from no knowledge to a working vocabularly of around 200 words. Although the amount of vocabularly is small, these words are reinforced hundreds of times throughout the course so the learner will know these words very well indeed. Pimsleur probably think that it's far more rewarding that a learner should know a few core words well with perfect recall than a larger number of words poorly.