Many American Indian languages make use of special syntactic patterns to distinguish among third-person participants in a sentence. Switch-reference is the name given to an unusual grammatical device that allows a speaker to specify whether the subject of one clause is the same as or different from that of another clause. Because of different cultural needs, American Indian vocabulary structure varies greatly, and some of the semantic concepts and sentence patterns often seem unfamiliar to those who have not grown up speaking the languages. In the Pacific Northwest, for instance, there are several unrelated genetic groups with strikingly similar, unusually complex consonant systems. Many languages of the Tupian family of South America have nasalization as an attribute, not just of vowels or consonants, but of whole syllables, and this feature has been borrowed by some unrelated neighboring languages.
Loanwords can reveal the prior history of a linguistic group.
Alaskan languages and some as far south as California have Russian loans, for instance, dating from the time of extensive trade with Russia, and borrowings from Spanish are common throughout California, the Southwest, and, of course, Latin America. Indian words have also been borrowed into English and and other European languages. The names of thousands of places throughout the Americas are of Indian origin. The Mayan hieroglyphic system, which has not yet been fully deciphered, was the only well-developed writing system in use in the Americas before European contact, although a number of the Central American civilizations and the Quechua used pictographic systems, primarily for religious purposes, and other groups made nonlinguistic petroglyphs. Most languages, however, do not yet have standard orthographies.