Quote 1
[Mr. Ewell says] "I seen that black n***** yonder ruttin' on my Mayella!" (17.84)
Mr. Ewell may be barely literate, but he's a veritable Shakespeare when it comes to offensive language. The way he phrases his accusation achieves an impressive feat of multitasking: it 1) dehumanizes Tom (he doesn't use Tom's name, or even the pronoun "he"), 2) emphasizes Tom's race over everything else (the redundancy of "black n*****"), 3) compares Tom to a beast ("rutting" is usually applied to animals), 4) portrays Mayella as a passive victim (she's the indirect object of the sentence), and 5) asserts power over his daughter ("my Mayella," as if Tom's trying to steal Ewell's property). Not bad for a mere ten words—no wonder the crowd goes wild.
Quote 2
Mr. Ewell kept the same distance behind her until she reached Mr. Link Deas's house. All the way to the house, Helen said, she heard a soft voice behind her, crooning foul words. Thoroughly frightened, she telephoned Mr. Link at his store, which was not too far from his house. As Mr. Link came out of his store he saw Mr. Ewell leaning on the fence. Mr. Ewell said, "Don't you look at me, Link Deas, like I was dirt. I ain't jumped your-" […]
"You don't have to touch her, all you have to do is make her afraid, an' if assault ain't enough to keep you locked up awhile, I'll get you in on the Ladies' Law, so get outa my sight! If you don't think I mean it, just bother that girl again!" (27.8, 12)
For Ewell, it's all about power—by scaring Helen he's declaring his power over her, but Deas is even scarier: he's got reputation and power in Maycomb, so he wins this round. Sometimes there are good reasons to be on the right side of the law.