We are introduced to this family at the end of the poem. It has a father, mother, sister, brother, and an other brother. The two younger brothers can read little words like “if and it” (59.4) while the father can wax multisyllabic with the likes of “Constantinople and Timbuktu” (61.1-3).
This mini-narrative shows child readers that their reading skills will grow as they do. Right now, they’re at the level of the two boys, but in time, they’ll acquire the skills to read larger, bigger, more impressive words. They just need to keep reading.
Of course, understanding why Constantinople got the works will remain a mystery no matter how old you are.