BERKELEY, CALIFORNIA—According to a Live Science report, historical linguist Johanna Nichols of the University of California, Berkeley, and her colleagues analyzed the structures of 60 languages found in the United States and Canada, and determined that they derived from two main language groups that left Siberia and entered North America in at least four distinct waves of migration. The analysis focuses on 16 features of the languages, including syllable structure, the gender of nouns, and how consonants are produced in speech. In the first main language group, the first-person pronoun has an “n” sound and the second-person pronoun has an “m” sound. In the second main language group, just one word can incorporate a sentence’s worth of information. The study also suggests that the first wave of migration, made up of people who spoke a diverse set of languages, occurred some 24,000 years ago. Then, about 15,000 years ago, people who spoke languages with the n-m pronouns entered North America. Just 1,000 years later, people who spoke languages with simple consonants arrived in a third wave of migration. Finally, the fourth wave brought complex consonants some 12,000 years ago, Nichols said. “It’s likely that the people who moved into North America left relatives in Asia,” she said, “and possible that some of those languages survive and have remained in Siberia,” she concluded. Read the original scholarly article about this research in American Journal of Biological Anthropology. To read about the languages and migrations of the ancestors of the Navajo and Apache, go to "Walking into New Worlds."