Stephen Greenblatt, "Learning to Curse: Aspects of Linguistic Colonialism in the Sixteenth Century," in Greenblatt, Learning to Curse: Essays in Early Modern Culture (N.Y., 1990), 16-39.
Examining European literary texts from the late 16thC, Greenblatt uncovers an imperialism that is linguistic in nature. The propagation of the English language became, early on, a primary goal of the colonial project. Analyzing cultural symbols, Greenblatt discovers that "to a ruling class obsessed with the symbolism of dress, the Indians' physical appearance was a token of a cultural void. In the eyes of Europeans, the Indians were culturally naked." (p. 17). Kidnapping of interpreters also provides evidence for the centrality of language. Gregorio Garcia, author of a history of the Indians, viewed the cacophony of Indian tongues as the work of Satan intended to impede the progress of Christianity. Though people like Las Casas viewed Indian language as important and meaningful, they were the exceptions.
Indians Had No Language
The prejudice of the learned was far more pervasive than amongst the rude sea captains, who had to deal directly with the "savages." Amongst the educated elite of Europe, mastery of language as evidenced by eloquence was powerfully linked to civilization. In addition, the Medieval figure of the Wildman lingered on in the Renaissance Humanist imagination. Educated Europe viewed the Indians as the lost descendants of Trojans, Hebrews, Carthaginians, etc. who had lost their power of language. (p. 21). The legacy of the Wild Man acted powerfully as a "rehearsal" for the encounter in the new world. Indeed, where other scholars have seen Shakespeare's Caliban as a noble savage, Greenblatt casts him as the Medieval Wild Man without civilization because he is without speech.
No Real Barrier to Speech
Yet, once the natives gained the gift of speech it was thoroughly European that they obtained. Writing of speeches delivered by native peoples, Europeans cast the speech in familiar terms -- putting words in their mouths that they would never have spoken. Speech, as truth, was universal. Once attained, eloquence in the mouths of natives was very like that of their conquerors. Even the Requerimiento becomes more intelligible in this light. Speech, for the Europeans, is universal.
The larger point that Greenblatt is making - Medieval and Renaissance Europe was conceptually unable to grasp the value of diversity, and this tendency was made even worse by the Enlightenment Liberalism to come. Claims of universality render unimportant the diversity of languages and of peoples. Liberal humanism discards people along with languages.
And you can also check out an interesting interview with Stephen Greenblatt from 1992 in which a journalist recounts a trip driving with Greenblatt along Interstate 91 from Cambridge to New Haven.