One adaptation frequently used by the the storyteller was the repetition of incidents. The description of an incident would be repeated a specific number of times (depending on the ceremonial number in the culture--three, four, five, or seven), with the hero killing that many monsters or that number of brothers who had gone out on the same adventure. This type of repetition was very effective in oral communication, for it firmly inculcated the incident in the minds of the listeners--much in the same manner that repetition is used today in radio and television advertising. In addition, there was an aesthetic value to the rhythm gained from repetition and an even greater dramatic effect, for the listener knew that when the right number of incidents had been told, some supernatural character would come to the aid of the hero, sometimes by singing to him. For this reason, oral literature is often difficult and boring to read. Oral literature also loses effect in transcription because the reader, unlike the listener, is often unacquainted with the worldview, ethics, sociocultural setting, and personality traits of the people in whose culture the story was told and set.

Because the effect of the story depended so much on the narrator, there were many versions of every good tale. Each time a story was told, it varied only within the limits of the tradition established for that plot and according to the cultural background of the narrator and the listeners. While studies have been made of different versions of a tale occurring within a tribe, there is still much to be discovered, for instance, in the telling of the same tale by the same narrator under different circumstances. These gaps in the study of folktales do not indicate lack of interest but rather the difficulty in setting up suitable situations for recordings.

The terms myth and folktale in American Indian oral literature are used interchangeably because in the Indian view the difference between the two is a matter of time rather than of content. If the incidents related happened at a time when the world had not yet assumed its present form, the story may be regarded as a myth; but, even if the same characters appear in the "modern" present, it is considered a folktale. Whereas European fairy tales traditionally begin with the vague allusion "once upon a time," the American Indian myth often starts with "before the people came" or "when Coyote was a man." To the Eskimo, it is insignificant whether an incident occurred yesterday or 50 years ago--it is past. Thus, while the mythology of nonliterate people has a historical development of its own, it cannot be admitted to the present-day classification of historical because it lacks documentation.

American Indian mythology can be divided into three major cultural regions: North American cultures (from the Eskimos to the Indians of the Mexican border), Central and South American higher civilizations, and the Caribbean and South American simpler cultures. Though each region exhibits a wide range of development, there are recurrent themes along the cultures, and the importance of mythology itself within each culture varies. In North America, for example, stories are not involved with a panoply of divine beings, whereas those of Middle America and South America bear some resemblance to the complicated mythologies of the surrounding higher cultures and are quite confusing with their many hybrid monsters and giants. In North America many mythologies (like the Dreaming of the Australian Aborigines) deal with a period in the distant past in which the world was different and people could not be distinguished from animals. These mythologies are related to the concept that all animals have souls or spirits that give them supernatural power. Because man has subsequently been differentiated from the animals, they come to him in visions, and in the stories they help the hero out of trouble. When there are many tales involving a single character, such as Raven, Coyote, or Manabozho, the transcriptions are linked together today and called cycles. Whether this cyclic presentation of tales is or is not indigenous to the Indian mind remains questionable, but it is used by folklorists who have been accustomed to legendary cycles of medieval European literature, such as the tales of Beowulf, La Chanson de Roland (The Song of Roland), or even The Canterbury Tales.

The body of American Indian folklore does not include riddles as found in African folklore, for example, nor does it include proverbs, though there are tales with morals attached.

The importance of mythology within a culture is reflected in the status of storytellers, the times assigned to this activity, and the relevance of mythology to ceremonialism. In many instances the relationship between mythology and ceremonialism is very close. The Navajo ceremonials, like the chants, are based entirely on the characters and incidents in the mythology. The dancers make masks under strict ceremonial control, and, when they wear them to represent the gods, they absorb spiritual strength. The Aztec ceremonials and sacrifices placate the gods who are the heroes of the mythology. If, however, the mythology consists primarily of animal tales and stories of personal and social relationships, the actors and characters involved in the stories are also an index to the beliefs and customs of the people.