From Empires of the Atlantic World: Britain and Spain in America 1492-1830, by John H. Elliott (Yale U. Press, 2006), Kindle Loc. 1598-1612:
Already the process of linguistic change was under way in New Spain, as Indians who moved into the cities picked up a working knowledge of Castilian, while Castilian words were simultaneously being incorporated into the Nahuatl vocabulary on a massive scale. Large numbers of the Indian vassals of the Spanish crown, however, either resisted the imposition of Castilian or remained to all intents and purposes outside its orbit, while many friars were inclined to ignore the crown’s decree. At the same time, creoles with indigenous nurses learnt in childhood the language of the conquered, and in the Yucatan peninsula, which had a high degree of linguistic unity before the conquest, the Maya language, rather than Castilian, became the lingua franca in the post-conquest era. The crown, for its part, was driven in particular by religious considerations to recognize realities. In 1578 Philip II decreed that no religious should be appointed to Indian benefices without some knowledge of the language, and two years later he set up chairs of indigenous languages in the universities of Lima and Mexico City, on the grounds that ‘knowledge of the general language of the Indians is essential for the explanation and teaching of Christian doctrine.’
The English, on finding themselves confronted by the linguistic barrier between themselves and the Indians, at first reacted much like the Spaniards. Indians showed little inclination to learn the language of the intruders, and initially it was the settlers who found themselves having to learn an alien tongue, both to communicate and to convert. Indians in areas of English settlement had less inducement than those in the more urbanized world of Spanish America to learn the language of the Europeans, although by degrees they found it convenient to have some of their number who could communicate in the language of the intruders. As the balance of forces tilted in favour of the settlers, however, so the pressures on the Indians to acquire some knowledge of English increased, until the colonists were securing promises from neighbouring tribes to learn the language as a requirement for submission to their rule. Here there was no question, as there was in Spanish America, of a policy of actively promoting, at least among a section of the colonial community, the learning of indigenous languages – a policy which had the concomitant, if unintended, effect of encouraging not only the survival but also the expansion of the major languages, especially Nahuatl, Maya and Quechua. The powerful impulse to Christianize that worked in favour of the toleration of linguistic diversity in Spain’s American possessions simply did not exist in British America.