- nominalizer, the particular one(s) that
- the particular...
Similar to the -ing suffix in English, the -ígíí suffix attached to a verb means "the particular one that does [verb]". In most cases, the enclitic -ígíí does not belong only to the word to which it is appended, it belongs to the entire phrase, so that naałniih yichʼą́ą́h naabaahígíí means "the particular one that fights to prevent disease" (immune system). Suffixed to a noun, it is often used like a definite article, indicating a particular one.
Thus naaʼnaʼ (“he/she/it crawls about”) + -ígíí ("-ing") produces naa´na´ígíí ("[the act of] crawling about").