The congruence bit of this post is obsolete.
The Sargaĺk copula is somewhat complicated – it is both morphologically defective, in lacking several forms that most other verbs have (specifically, it exclusively has indicative and a basic irrealis form. It lacks imperatives, and any other modal distinctions are just omitted). It also is morphologically extended, in having several forms that few and even no other verbs have. Some of the forms do not historically speaking derive from verbs, but from pronouns and participles, but are nevertheless syntactically and morphologically verbs by now. Adjective Congruence Sargaĺk has some congruence on its adjectives.
sg -ti -da
pl -er -so The above table marks the agreement marker in nominative and accusative noun phrases. The following set of markers appear with the pegative:
sg -ta -na
pl -sa -sair Beyond this, the only "normal" congruence markers are -er, which appears for all animate oblique case-number combinations, and -i, which appears for all inanimate oblique case-number combinations. The case markers used on nouns do appear on adjectives at times as well - including a zero marker for feminine and masculine nominatives. This invariably happens when the adjective is the head of an NP, i.e. constructions analogous to English '(a|the) ADJ one'. This also serves to intensify the adjective, or to mark topicality of the NP or to attract attention to the adjective. This specifically may happen when demonstratives are involved. Congruence
There are two copulas: one for clearly binary qualities or memberships of sets, one for qualities with degrees to them. Whether a quality is considered binary or not is very culturally determined - gender is binary, as is being asleep or awake. Being a father is not binary, but being a mother is; being a male is binary, being female is not. This goes with both nouns and adjectives, so this is in a sense another two-way division of the noun/adjective space in addition to gender and animacy.
Colours are generally not binary, except eye colours. Darkness of hair is binary, but light hair colours are considered binary. Hunger vs. satedness is binary, illness is not binary. Deadness and liveness is binary. Etc.
(The order for the verb forms given below is 1 p., 2 p., 3 p. masc, 3p. fem, the upper row being singular, the lower plural)
The two verbs are as follows:binary:
k'iʒ | k'ip | k'ir | k'iva
k'iko | k'iyo | k'ivo | k'ivo
k'aʒa | k'apa | k'ara | k'ava
k'avi | k'aya | k'ava | k'ava
əvin | əvi | əvir | əvo
əko | əvyo | əvo | əvo
an | avi | avir | ava
aki | ava | ava | ava
The perfective-imperfective distinction in the past binary form is unique to the copula. The future is not fully unique, although its formation for the different verbs that have it is not very regular at all.
(1pl has a thing where -i is an old inflection that appears in some verbs in the past tense.) A peculiar thing with the two copulas is that if the complement is a noun, and thus has intrinsic gender, the congruence marker for adjectives will appear as a suffix on the verb, giving forms such as k'iʒda, əviso, etc. With adjectives, there is no such congruence on the verb, but the adjective does show the gender-number congruence. These two verbs are the only verbs to show gender-number congruence with more than one constituent; we will later, however, find verbs that have congruence not with the subject, but with some other constituent – and for these, the congruence morphemes are the same as for the complement congruence here.
Causatives of the binary version imply a more perfective causation, whereas causatives of the non-binary imply increasing something's quality as something or other. For the causatives, the subject congruence is dropped altogether.