stems can be formed in several ways: reduplicative: e.g. gäddälo "kill" > gədaddälo. This form has a wide variety of meanings, mostly intensifying the verb in some way. passive/reflexive/intransitive tä- prefix: e.g. käffälo "pay" > tä-käffälo "be paid". A reciprocal action can be expressed by this prefix attached to a transitive verb with the vowel a after the first radical, or a reduplicative form, e.g. tä-gäddäl-mun or tä-gdaddäl-mun "they killed each other". causative or transitive of intransitive verbs a-: e.g. säkkäro "be drunk" > a-säkkäro "get someone drunk"; näddädo "burn (intr.)" > a-näddädo "burn (tr.)". causative of transitive or passive verbs at- (+ -i-): e.g. käddäno "cover" > at-kiddäno "cause to cover" or "cause to be covered". Added to the -a- form, it expresses reciprocity and adjutative (helping): atgaddälo "cause to kill one other" or help to kill". Some verbs are formed with initial ən- or tän-; the only derived stem from these is the a- stem, with a- replacing ə- or tä-. E.g. ənkrättäto "be bent" > ankrättäto "bend". There are two tenses/aspects, perfective (past) and imperfective (non-past); each has distinct forms for main versus subordinate clauses, and positive versus negative. There are also distinct jussive, imperative, and impersonal forms. Conjugations Perfect The form with suffixed -m is used in subordinate clauses to connect verbs not otherwise connected, in a way analogous to Japanese -te; it can be translated as "and", as a gerund, or as a resultative. The perfect in -m followed by näbbär forms the pluperfect. The negative perfect is formed by prefixing al-, with vowel change; for the conjugations mentioned above, the resulting forms are al-säfärä, al-täkkälä, and al-č'afärä. Examples: ge aräššo "he built a house"; banätäw k'ən awänna-m bämida tonnaw "having put butter on the top of his head, he sat outside". Imperfect Like the perfect, the subordinate forms can take the suffix -m to express a series of non-past actions. This can be combined with näbbär to express a habitual past action. Examples: ahoññ gäbäya nalfu "today we shall go to the market"; yəgädəl məss "the man who kills"; mas tənäsa-m yibara wawt'a tək'ärsi "she picks up the sleeping mats and begins to remove the dung." It can be augmented by -ən, with no obvious change in meaning. Examples: ahoññ yəmät'a timäsəl "it does not seem that he will come today"; ädahʷan t-aykäfəl alläfo "he left without paying his debt". Jussive and Imperative These