The Summer Institute in Linguistics is the linguistic arm of evangelical churches in the United States. It runs the website Ethnologue which maps languages around the world. The SIL was particularly involved in South and Central America in using missionaries to help oil companies move local indigenous peoples off their land so that oil corporations could then drill.
from wikipedia on it's missionary activities...
SIL has been accused of being involved in moving indigenous populations in South America from their native lands to make way for exploitation schemes of North American and European oil corporations. The most well known example is the case of the Huaorani people in Ecuador, which resulted in many deaths and the moving of the people into reservations controlled by the missionaries.
In 1975, thirty anthropologists signed "The Denouncement of Pátzcuaro", alleging that SIL was a "tool of imperialism", linked to the CIA and "divisions within the communities that constitutes a hindrance to their organization and the defence of their communal rights".
In 1979, SIL's agreement with the Mexican government was officially terminated, but it continued to be active in that country (Clarke, p. 182). The same happened in 1980 in Ecuador (Yashar 2005, p. 118), although a token presence remained. Remnants of SIL presence were protested in every subsequent Indian uprising. In the early 1990s, the newly-formed organisation of indigenous people of Ecuador CONAIE once more demanded the expulsion of SIL from the country.
At a conference of the Inter-American Indian Institute in Merida, Yucatan, in November 1980, delegates denounced the Summer Institute of Linguistics for using a scientific name to conceal its religious agenda and capitalist worldview that was alien to indigenous traditions
John Perkins provides an example of criticism of SIL activity:
I had heard that (Jaime Roldos, President of Ecuador, 1979-81) accused The Summer Institute of Linguistics (SIL), an evangelical missionary group from the United States, of sinister collusion with the oil companies. I was familiar with SIL missionaries from my Peace Corps days. The organization had entered Ecuador, as it had in so many other countries, with the professed goal of studying, recording, and translating indigenous languages.
SIL had been working extensively with the Huaorani and Matsés tribes in the Amazon basin area, during the early years of oil exploration, when a disturbing pattern appeared to emerge. While it might have been a coincidence (and no link was ever proved), stories were told in many Amazonian communities that when seismologists reported to corporate headquarters that a certain region had characteristics indicating a high probability of oil beneath the surface, SIL went in and encouraged the indigenous people to move from that land, onto missionary reservations; there they would receive free food, shelter, clothes, medical treatment, and missionary-style education. The condition was that they had to deed their lands to the oil companies.
Rumors abounded that SIL missionaries used an assortment of underhanded techniques to persuade the tribes to abandon their homes and move to the missions. A frequently repeated story was that they had donated food heavily laced with laxatives - then offered medicines to cure the diarrhea epidemic. Throughout Huaorani territory, SIL airdropped false-bottomed food baskets containing tiny radio transmitters; The rumor was that receivers at highly sophisticated communications stations, manned by U.S. military personnel at the army base in Shell [a frontier outpost and military base hacked out of Ecuador’s Amazon jungle to service the oil company whose name it bears], tuned into these transmitters. Whenever a member of the tribe was bitten by a poisonous snake or became seriously ill, an SIL representative arrived with antivenom or the proper medicines - often in oil company helicopters."
SIL was allegedly financed initially by expatriate coffee processors in Guatemala, and later by the Rockefellers, Standard Oil, the timber company Weyerhauser, and USAID. [...] By the 1980s, [SIL] was expelled from Brazil, Ecuador, Mexico, and Panama, and restricted in Colombia and Peru.
In response to the allegations that Perkins published, SIL posted the following on their website (SIL Responds to Errors in "Confessions of an Economic Hit Man"), referring to an earlier (2004) publication of the book:
John Perkins in Confessions of an Economic Hit Man, makes a number of egregious errors in fact and presents false statements about SIL's activities in Ecuador in the 1950-60s. The comments are based on rumors that have never been substantiated and are contrary to documented eyewitness accounts. Throughout its 70 year history, SIL (Summer Institute of Linguistics) has been an active advocate and supporter of indigenous language communities in Latin America and around the world. SIL entered Ecuador in 1953 in response to the expressed invitation of then President Galo Plaza to study, record and work on translation of materials into indigenous languages. SIL performed the work it was invited to do and maintained a full reporting relationship with Ecuador's Ministry of Education through 1982. At the urging and support of many indigenous communities, respected journalists, and civic leaders the government granted visas to certain SIL members to continue their activities until work was completed in 1992. SIL's linguistic research work was donated to local universities and is a matter of public record. Today a number of indigenous groups in eastern Ecuador enjoy their protected land as a result, in part, to SIL's advocacy before the government.
Perkins contends that SIL worked under the sponsorship and in support of oil companies in the Amazon. This is absolutely untrue. SIL has had no involvement with oil exploration and has never had any agreements with oil companies or any other parties to promote oil exploration. In fact, SIL members were known to have intervened to prevent violence between indigenous communities and oil company workers. Further, the accusation by Perkins that SIL has received support from the Rockefellers in Amazonia is also false. SIL has never received funding from the Rockefeller Foundation.
For more read Thy Will Be Done: The Conquest of the Amazon : Nelson Rockefeller and Evangelism in the Age of Oil by Gerard Colby and Charlotte Dennett.