pronunciation of single hanzi (only the most used nowadays), with translation in english; 50% means that if you know those 152 hanzi you can understand about 50% of what someone says o write in chinese; 75% (329 words) and 90% (571 words) means the same thing; globally 1052 words to understand 90% of the chinese: that's great! (if can memorize 1000 things)