Page "Na-Dene languages" Paragraph 13

All of these languages share a highly complex prefixing verb structure in which tense and mood markers are interdigitated between subject and object agreement markers.

The morphological hallmark of the family is a series of prefixes found directly before the verb root that raise or lower the transitivity of the verb word.

These prefixes, traditionally known as " classifiers ", derive historically from a combination of three distinct classes of morphemes and are not found in any other Native American language family.