Maniac loves trash talk because the words “have spirit” and trash talk makes him feel included.

Trash talk, or swearing, is something that Maniac learns from playing with boys in the neighborhood. 

Maniac learns trash talk playing sports in a vacant lot.  He enjoys playing with the other boys because he is a fast runner.  At first he does not talk, Hands Down does it for him, and every time he makes a touch down Hands Down is there talking trash.

Every time he scored a TD or cracked a home run, Hands was bent over in his face, talking trash. "Do it, man! Smoke them suckas! Poke 'em! Joke 'em! You bad-dudin' it! You the baddest! Five me, jude!" (Ch. 15)

This makes him feel included, as if he is part of a group.  He has something he is good at, and a place where he is valued.  The trash talking is the other boys’ way of showing that they are making him part of the gang and showing that he is one of them and doing a good job.

Maniac enjoys the trash talk.

Maniac loved trash talk. The words were different, but in some strange way they reminded him of church. It had spirit, it had what they called soul. Pretty soon he was talking trash with the rest of them. (Ch. 15)

Unfortunately, the family he is living with does not enjoy the trash talk.  Mrs. Beale at first cannot believe that Maniac is talking like this.  Then she slaps him.  He responds by “burying his face in her chest and sobbing, "I love you... I love you...""(Ch. 15).

This incident, between Mrs. Beale and Maniac, shows that Maniac finally has a family. He is so happy that someone finally cares what happens to him, or what he does and says.   He has a home now, and a mother.  The trash talk was about fitting in with the boys, but crying when Mrs. Beale slapped him was about having a home.