You misread. A course is 40h (20 classes), and it takes 10 courses to get reasonably conversational. i.e. 400h of class-time (not counting homework, study, and

You misread. A course is 40h (20 classes), and it takes 10 courses to get reasonably conversational. i.e. 400h of class-time (not counting homework, study, and practice in the wild time)