Now that Oskar can't go to school, his parents resign themselves to the idea that he'll be ignorant his whole life.
Oskar doesn't talk all that much as a child, since he prefers to communicate by drumming. His parents take this as a sign that he's slow or dim-witted.
Oskar tries several times to find an adult who will teach him his ABCs, but his first few attempts fail. It's only after a bit of trial and error that he comes across Frau Greff, the wife of Alfred Matzerath's friend Greff, who runs a fruit and vegetable shop.
Greff's so obsessed with his business and his Boy Scouts (he's a troop leader) that he pays no attention at all to his wife. Oskar's suggesting here that Greff is sexually attracted to the boys in his troop.
So that brings us back to Frau Greff, who lies in bed all day with nothing to do. When Oskar starts hanging out around her, she's immediately energized.
But it's not because she wants to teach him stuff. It's because she wants to dress him up like a baby, since she doesn't have children of her own and has always dreamed of having them.
Oskar's willing to go along with this ridiculous performance as long as he can learn how to read. And he eventually does.
Slowly, he tears pages out of Frau Greff's books and takes them home to read in secret.
Frau Greff thinks Oskar is too stupid to learn, but he's actually a genius (according to him).
While reading to Oskar, Frau Greff comes across a book about the Russian seducer named Rasputin.
In this book, there are all kinds of naughty descriptions about orgies and sex. Frau Greff loves to read about it out loud, which she only does in front of Oskar because she thinks Oskar doesn't understand what she's talking about.
Eventually, Frau Greff starts inviting Oskar's mother to join in on the reading. The two of them start to spend entire afternoons reading the pornographic material together, laughing and feeling scandalized. Oskar sits in the wings and keeps learning.