Ordine de argumentu (index):
transitivos e intransitivos (transitive and intransitive verbs)
attivos e passivos (active and passive modes)
de riflessu (reflexive verbs)
raighinas e desinenzas (roots and endings)
sos tempos (the tenses)
sos modos (the modes)
s'indicativu (the indicative)

Verb page 2, Content:
su congiuntivu (the subjunctive)
condiscionale (conditional)
s'imperativu (the imperative)
modos indefinidos (indetermined modes)
infinidu (infinitive)
participiu (participium)
gerundiu (gerundium)

Verb page 3: ausiliares (auxiliary verbs)

Verb page 4: conjugasciones (conjugations)

The verb is the part of the argument that informs us about the subject of the phrase. This information is:

an action performed by the subject
Antoni lezet unu liberu (Antoni reads a book)

an action done to the subject
Pedru est istadu pagadu deris sero (Peter has been payed last night)

a condition of the subject
Pedru istat in s'atera carrera (Peter lives in the other street)

a characteristic of the subject
Antoni est revessu che mulu (Antonio is stubborn as a mule)

the existence of the subject
ch'est Antiogu puru (there is Antiogu as well)

Another function of the verb is to gather information in time.
In Sardinian, depending on the information the verbs give us, they can be: transitive if the action the express is directed from the subject to an object, intransitive if the action is about the subject itself.

Transitive

iscrio una litera (I write a letter)

intransitive

como so manighende (now I am eating)

The verb is in the active form when the subject performs the action or better, when the subject plays an active role in the activity indicated by the verb.

Pedru samunat sa machina (Peter washes the car)

The verb is in the passive form when you want to put in evidence the subject undergoing the activity, but in the Sardinian there is no real passive form: normally a passive form is constructed using the third person in the plural without a subject or the third person in the singular or in the plural, preceeded by the reflexive pronoun si (corresponding to the impersonal forms "one" or "they" in English).

sa machina la sun samunende (the car is being washed) (the car it they-are washing)

su computer l'an bendidu deris (the computer has been sold yesterday) (the computer it they-have sold yesterday)

si narat chi ses macu (they say you are mad) (one say that you are mad)

si passan cue los mazzana (if they pass by there, they will be slain) (if they-pass there them they-slay)

The use of the word nanchi, nachi (corresponding to "they say that") is tipical in the speaking of Sardinian:

nachi ti an promossu. Beru este? (they say you have been promoted. Is it true?) (they say that you they-have promoted. True it-is?)

nanchi on bi enis pius. De aberu este? (they say that you don't come there anymore. Is that true?) (they say not there you-come more. Of truth it-is?)

Besides the active form and the passive form, which I repeat is not common in Sardinian, there is the reflexive form.
The reflexive form occurs when when the subject performs an action leading back to itself. In this case, the verb is preceeded by the pronominal particle except for in the gerundium and the imperative modes, where the pronominal particle come after.

mi (me/myself)
ti (you/yourself)
si (him/himself, her/herself, it/itself, one/oneself)
nos (us/ourselves)
bos (you/yourselves)
si (them/themselves)

eo mi samuno (I wash myself)
tue ti samunas (you wash yourself)
samunendemi (washing me/myself)
samunati (wash yourself)
non si cheret samunare (he does not want to wash himself) (not himself he-wants to wash)

The verb is variable in number, person, time and mode. It is created by a root that always remains the same and an variable ending that indicates the subject, in order to establish time and  mode, person and number for that same subject.

Person and number
The ending of the verb changes according to the person and the quantity in order to distinguish the subject.
The verb can be in the singular or in the plural.
The persons are:
in the first person when the subject gives the message of eo, (deo) or nois (I, we)
in the second person when the subject is tue or bois (you, you)
in the third person when the subject is isse, issa or issos, issas (he, she, it, they)

So the verb in total has six endings that corrispond to the six persons that have the function as subjects.

Examples: Let us take the voice of the verb faeddare (to speak) in the present:

three singular forms

1. eo faeddo (I speak)
2. tue faeddas (you speak)
3. isse faeddat (he speaks)

and three plurals

1. nois faeddamus (we speak)
2. bois faeddades (you speak)
3. issos faeddana (they speak)

in the examples above, it can be noticed that to the verbal root faedd (speak) the number can be identyfied when you add a different ending for each person.
In conclusion, the verbal root remains the same for every tense and person whereas the ending varies for all the persons and tenses, but these endings are the same for almost all the verbs.

Through changes of its ending, the verb presents an event showing the period of time in which an action takes place in corrispondence with the person that expresses it.

The tense can be present

eo naro (I say)

past

eo naraia (I said)

future

eo appo a narrare (I shall say)

therefore:

the contemporary tense is the present only

eo faeddo (I speak)

the past tenses are divided into

perfect

appo faeddadu (I have spoken/ I spoke)

imperfect

eo faeddaia (I spoke)

pluperfect

eo aia (aio) faeddadu (I had spoken)

past historic (only in some areas of Sardinia)

eo faeddei (I spoke)

the posterior tenses are divided into

future

eo appo a faeddare (I shall speak)

tue as a faeddare (you will speak)

tue des faeddare (you will speak)

future perfect

eo appo 'e aere faeddadu (I shall have spoken)

tue as aere faeddadu (you will have spoken)

tue des aere faeddadu (you will have spoken)

As it can be seen, the tenses consist of two forms: simple and composed
Simple when it consist of one verb only, constructed by root and ending.
Composed when the tense is created by a form of the auxiliaries essere or aere or devere/ deppere (to be, to have, shall)

The modes of the verb consist of two categories: finidos and indefinidos (finite and indefinite)
The finite modes distinguish the different persons through the endings that can have the function of an object or of a subject. They are:

Indicative with the tenses

in the present

in the past: imperfect, perfect, past historic, pluperfect

and in the future: future, future perfect

Subjunctive with the tenses

in the present

in the past: imperfect, perfect, pluperfect

Conditional with the tenses

in the present
in the past

Imperative present and future

Indefinite with the modes

infinitive in the present and in the past

participle present and past

gerund present and past

The indicative is the verbal mode indicating the reality, facts that are certain or true or at least presented in that way.
In Sardinian the indicative has seven tenses: three simple tenses (present, imperfect, historic past) and four composed tenses (future, future perfect, perfect, plusperfect)

The present eo cabulo (I walk), indicates the contemporanity of the action regarding to the moment in which it takes place.
However, the present tense can also indicate facts that are not happening contemporarily, namely
an action that is repeated regularly

example:

Babbu ch'essit sempre a sas sette (my father always goes out at seven)

An action taking place in the past:

M'ammento chi fimus tottos duos, eo e babbu, affaca a sa tziminea abbaidendendos su fogu, onzunu pessente a isse: cando, a s'ispessada intrat Bobore tottu indiauladu, a ragas faladas e cun sa giachetta istratzulada, chena mancu saludare lestru lestru che curret a su fusile, l'ischit isse cun cale intenzione intro 'e cussa conca piena 'e 'inu.

I recall that my father and I were sitting by the fireplace, looking into the flames, both of us were absorbed in our own thoughts when, suddenly, Bobore enters in a fury, with his trousers down and  his jacket torn. Without so much as a greeting as he runs quickly to get the gun with who knows what intention in that drunken mind of his.

(I recall that we-were both of us, I and father, next to the fireplace looking-us the fire, each of us thinking to him: when, suddenly, and not enters Bobore, at trousers fallen and with the jacket torn, without even to greet quickly quickly as he runs to the gun, that he-knows he with what intention inside of this head full of vine.)

An action that will happen for sure in the future:

Besso como (I go out now)
Palto cras manzanu a sas otto (I leave tomorrow morning at eight)

The imperfect eo faeddaia (I spoke) indicates the durative aspect of an action in the past.
This is used to talk about an action that have already taken place:

eo andaia a mi setzere accurtzu a s'essida in unu taulinu solu pro mene; ma b'istaia pagu solu ca luego bi eniat calecunu a percossare.
I went to sit all by myself at a small table by the door, but I was alone for just a short while, then soon someone came to disturb me.
(I went to me sit next to the exit in a table-small only for me; but there I-was little alone because after there came someone to disturb)

To describe a person or an object:

Aiat sos ojos in sambene, su bonette a s'Orgolesa untu de mugheddu si che l'aiat giradu a daisegus, leait fua cun sas manos ch''idias e non bidias a sa lughe de sa luna e sa oghe che l'essiat che campana gioghende cussa murra a sa tzega.
He had red eyes, the Orgolese hat was greasy and dirty and he had turned it backwards, he was fast with his hands in the moonlight, one moment you saw them, the next you did not, and his voice rang out like a bell as he played the "morra" in the dark.
(He-had the eyes in blood, the hat in the Orgolese dirty of grease for-him that it he-had turned backwards, fast he-was with the hands that you-saw and not you-saw in the light of the moon and the voice that him came out as bell playing this morra in the dark)

To indicate a repeated action in the past:

S'annu passadu b'andaia de frequente a domo sua (last year I often went to his house)

This tense indicates a happening in the past that still has an effect in the present. It is composed by the present of the auxiliary verb and the past participle of the verb that is to be conjugated.
Examples:

Minde so 'ennidu a innoghe dae pius de vint'annos. (I have come here for more than twenty years)(Me-of-there I-am come to here from more than twenty years)

So abbarradu isettende un'oretta dae poi mi che so andadu. (I was waiting here for an hour then I went away)(I-am remained waiting an hour from then me of-there I-am gone)

This tense indicates an event finished in the past. It is used in the narrative texts in alternance with the imperfect.
Examples:

Fit pighende in d'una iscala fraziga chi sutta su pesu sou non rezeidi e nde faleidi che contone. Mortu. (He was ascending the wormeaten stairs which did not hold his wieght and thus he fell down like a rock. Dead.)(He-was ascending in the stairs wormeaten which under his weight own not bear and of-it fell as stone. Dead.)

The plusperfect indicates an event happening in the past before another event in the past.
In the Logudorese Sardinian today, the conditional is often used in its place.
Plusperfect is composed by the imperfect of the auxiliary verb and the past participle of the verb that is to be conjugated.
Examples:

Aia lassadu sa gianna aberta apposta pro isse ma non fit bennidu. (I had left the door open for him but he did not come)(I-had left the door open on purpose for him but not he-did come)

Fia 'ennidu si m'aiazis giamadu (I would have come if you had called me)(I-had come if me you-would-have called)

Fia andadu (I would have come)

Aia lassadu sa gianna aberta si l'aia ischidu (I would have left the door open, had I known)(I-had left the door open if it I-had known)

To indicate something that is yet to come. In Sardinian the grammatical future is a verb composed by the the present indicative of the auxiliary aere (to have) and the preposition a (to) and the infinitive of the verb you want to conjugate.
Examples:

Appo a bennere cras, si tottu andat bene (I shall come tomorrow if everything is going well)(I-have to come tomorrow if all goes well)

Appo a finire dae poi si bi resesso (I will stop afterwards if I can)(I-have to finish after if there I-succeed)

An 'a bendere como chi su babbu non ch'est pius (Of course they will sell, now that the father is no longer alive)(They-have to sell like that the father not there is more)

The future perfect indicates an event that has to be completed before another event, also in the future, can take place.  In Sardinian the future perfect is created by the present indicative of the verbs aere (to have) or devere (shall/ ought to) and the inifinitive of the verbs aere or essere (to be) with the past participle of the verb to conjugate.
Examples:

A cuss'ora app'aer manigadu beni a mi leare. (At that hour I will have eaten, so come and pick me up)(At that hour I-have-to have eaten come to me pick up)

A cuss'ora depp'aer manigadu beni a mi leare. (At that hour I will have eaten, so come and pick me up)(At that hour I-will-to have eaten come to me pick up)

A cuss'ora app'a esser partidu non benzas pius. (At that hour I will be gone so do not come)(At that hour I-have-to be gone not come(you) more)

Beni puru chi cando a tando gia an''aere fattu e bai 'essides (azis a bessire) impare. (Feel free to come, by then they will have finished, so that you can go out together)(come only because to when to then already they-have-to have finished and so you-go-out (you-have to go out) together.

Den''aer appidu cosa! Anda e pregunta. (Something must have happened! Go and ask [them])(It-will-to have happened something! Go and ask).