In Louise Erdich's poem Dear John Wayne, who is the narrator in much of the poem, and who speaks the italicized lines?  Also, there are curious shifts in the diction, for instance from"some...

Louise Erdich is of Native American ancestry.  The “Western” is a genre of film much reviled for its historical depiction of Native Americans.  John Wayne was the embodiment of the American West, and was considered the living symbol of American machismo and patriotism.  “Dear John Wayne,” is Erdich's indictment of the culture that celebrated the images personified – or so the stereotype has it – by Wayne in the films that denigrated as subhuman Native Americans while glorifying in their destruction.  It is fair to suggest that the narrator is Erdich herself, imbued as she is with a strong sense of her American Indian identity.

Films depicting the conflict between white settlers and the indigenous tribes on whose land the former routinely settled often provided crude depictions of those tribes.  “Dear John Wayne” is narrated by an individual who, together with at least one other person – and probably only one, given their position “on the hood of the Pontiac” – is viewing a film at a drive-in theater, itself a remnant of the past.  The poem is replete with images and symbols, most grounded in Native American or mythological tradition.  The meanings are invariably left to the individual reader to decipher.  For example, when the narrator describes “this wide screen beneath the sign of the bear,” she could be referring to the constellation “Ursa Major,” or she could be using the “sign of the bear” in a more parochial, Native American context, in which it symbolizes strength and, when provoked, ferocity. 

Attempts at explaining apparent changes in diction are entirely subject to interpretation.  Vanquishing “the hordes of mosquitoes,” for instance, can easily, in the given context, be a metaphor for the blood-thirsty compulsion of Europeans to vanquish the indigenous peoples standing between them and the land and resources they coveted.  Consequently, analyzing the phrases “The Sioux or some other Plains bunch” and the use of the word “parlance” (“there will be no parlance.”) for dissimilarities in diction assumes a conscious effort on the part of the poet that may or may not exist.  Erdich is a member of the Ojibwe, or Chippewa – a distinct tribe.  Reference to the Sioux could have been for poetic purposes or because that was the tribe being decimated by the whites in the film, although the Plains Indians were primarily in the Dakotas.

When the narrator describes “A few laughing Indians fall over the hood slipping in the hot spilled butter,” she could be describing the scene at the drive-in theater – a venue where people got out of their cars, walked to the snack bar and purchased their popcorn, which they would then carry back to their cars – but is almost certainly referring to the culturally devastated peoples whose lives have been reduced to dire levels of economic destitution with rampant drug and alcohol problems.  Or, “hot spilled butter” could be a metaphor for the blood spilled by her ancestors.  The final stanza of the poem is an indictment of the cavalier and brutal manner in which the Americans John Wayne purportedly represented ran roughshod over entire nations:

"Come on, boys, we got them

Where we want them, drunk, running. . .

Even his disease was the idea of taking everything.”

“Dear John Wayne” is a comment on the destruction of Native Americans.  We took their land and instead of fields of corn we planted nuclear-armed missiles (“ICBM missiles”).