humans/lightning → infants/big animals → mid-size animals → small animals → insects → natural forces → inanimate objects/plants → abstractions Generally, the most animate noun in a sentence must occur first while the noun with lesser animacy occurs second. If both nouns are equal in animacy, then either noun can occur in the first position. So, both example sentences (1) and (2) are correct. The yi- prefix on the verb indicates that the 1st noun is the subject and bi- indicates that the 2nd noun is the subject. But example sentence (3) sounds wrong to most Navajo speakers because the less animate noun occurs before the more animate noun: In order express this idea, the more animate noun must occur first, as in sentence (4): Although sentence (4) is translated into English with a passive verb, in Navajo it is not passive. Passive verbs are formed by certain classifier prefixes (i.e. transitivity prefixes) that occur directly before the verb stem in position 9. References See the Southern Athabaskan languages bibliography for references Southern Athabaskan languages