In "Next to of course God America I", discuss the sound devices, the sentence devices and the structure devices.
Alliteration is used in E.E. Cummings' "next to of course god america I": "Love your land" in line 2, "glorious name by gorry" in line 7, "jingo by gee by gosh by gum" in line 8, "heroic happy," line 10, and "like lions," line 11. Interpretations of this poem vary so greatly that nailing down the effect of the alliteration may be difficult.
In short, in this poem the alliteration seems to have the effect of adding to the sense of nonsensical rambling created by the poem. Alliteration creates unity and when initial consonant sounds are repeated often and closely together, the seriousness of the piece lessons. It's similar to the use of obvious, quickly repeated rhymes in nursery rhymes or many pop songs. Don't misunderstand: the underlying content of the poem is serious, but the speaker himself is probably being mocked.
The speaker, while giving his speech, is obviously rambling, however one interprets the content of the piece, and I'd suggest the alliteration contributes to the sense of the rambling.
That treats one of the sound devices used in the work. Since your question has multiple parts to it, I'll let other editors handle the rest.