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It is important to note that the Euro-American view of a single group, the Native Americans, is entirely false. At the beginning of European colonization of the Americas in the late 1400s CE, there were likely well over 200 languages, grouped into somewhere around 60 language families and language isolates (Campbell and Mithun 1979: 39-46). Language isolates are languages that do not share a common ancestry with other languages, essentially making them their own language family.
In addition to these languages, there were pidgins--limited trade languages not spoken natively by anyone--used in North America. Though we're less certain for Pidgin Delaware (used primarily in what is now Delaware and New Jersey), Mobilian Jargon (used primarily along the Gulf Coast and inland along the Mississippi River as far north as Illinois), Chinook Jargon (used throughout the Pacific Northwest), and Plains Sign Talk (a manually-coded pidgin used throughout the American and Canadian Great Plains) have some evidence to be in existence before European colonization. On top of this, you have more interesting languages, like Michif, a mixed language combining (primarily) elements of French and (Plains) Cree.
Multilingualism in North America was the norm, as is true in most of the world. Speakers were used to learning other languages, to a number of competencies. As Euro-American settlers traded with the Native peoples of the interior of North America, and as their settlements pushed west, the influence of English increased. Thus, we have established in the Plains and elsewhere pidginized English, what we now might call American Indian Pidgin English^(1).
Recognizable features of this stereotypical form of English used by Native peoples can be found even as far back as the 1600s CE. Leechman and Hall (1955) cite this particularly old quotation from an account at the start of King Phillip's War, in 1675 CE:
'About the 15th August (1675), Captain Mosley with sixty Men, met with a Company, judged about three hundred Indians, in a plain Place where few trees were, and on both Sides Preparations were making for a Battle; all being ready on both sides to fight, Captain Mosely plucked off his Periwig, and put it into his Breeches, because it should not hinder him in fighting. As soon as the Indians saw that, they fell a Howling and Yelling most hideously, and said, Umh, umh me no stawmerre [stomach?--D.L.] fight Engismon, Engismon got two Hed, Engismon got two Hed; if me cut off un Hed, he got noder, a put on beder as dis; [emphasis mine--/u/limetom] with such like words in broken English, and away they all fled and could not be overtaken, nor seen any more afterwards.' Charles H. Lincoln, ed., Narratives of the Indian Wars 1675-1699 (New York, 1913), p. 39.
In addition to the obvious sound changes (English this > Pidgin dis), there are grammatical simplifications common to many other pidgins, like fact that the articles a/an and the are no longer used, or that nouns only appear in their singluar form (Pidgin two hed, cf. English two heads). An important change, and one of the more noticeable ones--but certainly not confined to American Indian Pidgin English^(2)--is the use of verb-um (or a number of other spellings). This is a marker to show that the verb is used transitively--meaning it takes a direct object. This is a common feature of pidgin Englishes, so we unsurprisingly find it in New England during the Indian Wars, as well as later on the Great Plains during the Removal two hundred years later.
It should also be noted that both the United States and Canada engaged in policies of forced assimilation, removing Native children from their communities and placing them in boarding schools where they were forced to learn English and assimilate to white, Euro-American standards. In part, this is why even in Native communities where their native languages are still hanging on, pidgin Englishes have died out among all but the oldest Native peoples of North America.
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