In his poem "My Parents," Spender evokes a world in which the speaker's parents, despite their efforts, could not protect him from the rough, poor children who lived nearby. These boys in their torn, ragged clothes resented the speaker and made fun of his lisp. When he says that they "sprang out" from behind hedges "like dogs to bark at my world," the latter phrase is a simile, a comparison that uses the words like or as.

To the speaker, the rough boys who jumped out at him were as frightening as barking dogs. He likens them to dogs, who can be startling and loud, as well as incomprehensible and violent. This comparison helps form a vivid image in our minds of how scary the rough boys seemed to the speaker.

The young speaker had little understanding of the boys who tormented him: they came from a world so different from his it seemed as if they were a different species. He couldn't always truly understand the words they said to him, but he knew they could hurt him and mock him—and, worse, that they never smiled at him. Even looking back years later, he feels some bitterness at what he was subjected to and finds it hard to be forgiving.