Why is the "Let's Speak" App so effective for learning English? 40.000 Books ★ 290 genres of books Books in various genres make it simple to select your favorite books. ★ Learning vocabularies from books According to Hulstijin and Laufer (2001), Vocabulary acquired through natural learning will be stored in long-term memory. ★ Stimulating analytical thinking This is a good way for developing mental concentration while reading, thinking, and analyzing a story. ★ Improving speaking and writing