How did Squanto interpret for the Pilgrims and Massasoit?

Earlier in his life, Squanto had been taken to London by an unscrupulous person who tried to sell him and several other native people into slavery. Squanto and some of the others were rescued by local friars who taught him English and instructed him in Catholicism. When he finally was able to return to America, he was fluent in English and able to serve an interpreter for the Pilgrims and the Massasoit.