The idea behind the origin of the Navajo word bilagáana is not entirely clear. It’s meaning is, though. It’s the Navajo name for white people, or people of Caucasian descent.
Irvy Goosen, an author of Navajo language teaching texts, posits the idea that it evolved from the word “Americano.” Since spoken Navajo has a history of adopting words, and since it doesn’t actively use “m” and “r” it’s plausible that it went through an intense adaption process to get the word we have today. The English language is referred to as “bilagáana bizaad” in Navajo. Pronunciation: “bill-la-gáa-na” with the tone starting high and falling through the long vowel after the g.