Lesson 1 (15 words)
Lesson 2 (34 words)
Lesson 3 (54 words)
Lesson 4 (74 words)
Lesson 11 (85 words)
Lesson 12 (98 words)
Beginner (100 words)
Easy (500 words)
Medium 1 (1,000 words)
Medium 2 (2,000 words)
Difficult (3,000 words)
Advanced (4,000+ words)