Ilaini has only one class of verbs, which is regular except for contractions. Undoubtedly some irregular verb forms exist, but I haven't encountered them yet.
Disclaimer: I'm an amateur linguist, and this is a rough overview. Some grammatical terms may not be entirely correct, but I hope it's clear what I mean. If you spot any obvious mistakes, please feel free to send me mail and correct them.
As an example, I will use the transitive verb chala "to see", unless some other verb is clearer in the context. Chalyna has a "fossilised" punctual aspect marker and usually means "to look (at), to have a look".
|I see||I have seen||I'm about to see||I look|
|I saw||I had seen||I was about to see||I looked|
|I will see||I will have seen||I will be about to see||I will look|
|that I see, I would see||that I had seen, I would have seen||that I were about to see, I would be about to see||that I look, I would look|
|imperative||chalay, chalaye||-||chalesay, chalesaye||chalynay, chalynaye|
|see!||(go and) see!||look!|
|to see||to have seen||to be about to see||to look|
My old notes have a full set of participles as well (adjectives of Class II in -as), but in practice they turn out to be very rare and archaic. Where they exist at all, they serve as nouns or adjectives made from the verb.
The order of markers is (prefix)-STEM-aspect-tense-person/number. Prefixes, of degree or negation, are a matter of word-formation and will not be discussed here.
The unmarked form is the imperfective: chalan "I see" or "I am seeing". Note that Ilaini has no forms with exclusively progressive meaning, though the imperfective may imply that.
The perfective aspect is marked with -en-. It is used for actions which are already completed, or will be completed by the time indicated by the verbal tense: chalenan "I have seen", chalenin "I will have seen". Some perfective forms of verbs have taken on a meaning of their own, such as le rada "to decide", le radena "to be determined".
The inceptive aspect, marked with -es-, indicates that an action is just beginning or about to begin: chalesaye "you-plural are about to see" (for instance when announcing a performance), daysesut or, rather less colloquially, lea daysenesut "it started to rain".
The punctual (or non-progressive) aspect is marked with -yn- and indicates that an action takes place suddenly, momentarily, or only once. This can change the meaning so much that it's considered a separate verb: layna "to speak", laynyna "to say". If such a verb needs the punctual aspect, it can't get a second infix, so the meaning has to be expressed by adverbs. Other aspect infixes (-en- or -es-) do occur with these verbs, and the verb is then treated as though the stem ends in -yn-.
When verb forms get very long they're likely to be contracted by eliding parts of weak syllables or dropping them altogether. Notoriously weak syllables are unstressed -en- and-yn-. In this way, laynynenan "I have said" becomes laynyenan, chalesaye "you-plural are about to see" becomes chalsaye.
There are three tenses: present, marked with -a-, past, marked with -u-, and future, marked with -i-. The use of the tenses is straightforward: chalan "I see", chalun "I saw", chalin "I will see". The present tense is also used as "narrative present" when a story has already been set in time by starting with the past tense, as in the story of Grandpa and the Dragon.
The irrealis (or subjunctive) is formed like a tense, though it's more like a mood. The marker, which goes in the tense-infix slot, is -e-.
Verbs have first, second and third person singular and plural. Inclusive or exclusive first person plural (which can be marked in the pronouns) makes no difference for the verb forms. Dual subjects use the plural. Collective plural subjects use either the singular or the plural depending on context. There are also singular and plural imperatives for the second person: the imperative uses the second-person present tense forms.