 The verbs are all in the gerundive tense/aspect form.Some verb roots are defective in the sense that they must occur with either or both of the derivational prefixes.For example, from the root {"k'mt"} (3B) 'sit' there are the forms "täx'ämmät'ä" 'sit', "ax'ämmät'ä" 'cause to sit, put' but no form *"k'ämmät'ä".