When the subject is singular, the verb is in singular. The girl eats, the train arrives, my brother studies. The nucleus of the subject can be a noun, a pronoun, or a full noun phrase, but if it refers to a single entity, the verb form also stays in singular. The subject–verb agreement works the same in simple sentences and in broader structures, and helps keep clear the basic relation of the sentence, as in Word Order.

Agreement with singular subject

Idea
A singular subject requires singular verb.
If the subject is one, the verb also goes in singular.

A plural subject requires a plural verb: the girls eat, the trains arrive, my brothers study. The verb marks that the action or state is attributed to more than one referent. The plural of the subject can appear in a noun, a pronoun, or in an expression with several names. The verb form must reflect that number regardless of the subject's position in the sentence.

Agreement with plural subject

Idea
A plural subject requires plural verb.
If the subject has several elements, the verb goes in plural.

The person of the subject determines the verb form. I speak, you speak, he speaks, we speak, you all speak, they speak. Each person has its own verbal ending, and that ending changes even if the verb shares the same root. When the subject is a pronoun, the agreement immediately shows who performs the action. When the subject is a name, the verb form follows the person that name represents: María speaks is treated as third person, just like she speaks.

Agreement with the person of the subject

Idea
The person of the subject decides the form of the verb.
The third person uses a verb form different from the first and the second.

The subject can appear before or after the verb without losing the agreement. The professor explains and explains the professor are correct sentences; in both, the verb agrees with the professor. The change in order does not alter the number or the person of the verb. In Spanish, the subject may go after when you want to present the action first, the context, or an element already known. The grammatical relationship remains the same.

Agreement with preposed or postposed subject

Idea
The subject can go after the verb and the agreement remains the same.
Word order does not change the subject-verb relationship.

In Spanish, the subject can be omitted because the verb ending already indicates the person and number. I speak, you eat, they leave show on their own who acts. In a conversation, voy al mercado can mean I go to the market, and llegaron tarde can refer to they arrived late. When the subject is omitted, the verb form fulfills the function of identifying it. This is key in Subordinate Clauses, where the verb of each proposition may point to distinct subjects even if not expressed.

Agreement with omitted subject

Idea
When the subject does not appear, the verbal form shows the person.
The verb allows determining whether the subject is singular or plural.

When two or more subjects join with and, they normally form a plural subject and require a plural verb: Ana and Pedro study, the dog and the cat sleep, my sister and I go out. The sum of the referents changes the number of the subject, even if each part is singular separately. If the elements present themselves as a single unit very close, the plural verb remains the normal form. In this pattern, the union with and creates a shared subject that governs a single verbal agreement.

Agreement with subjects joined by and

Idea
Subjects joined by and usually require a plural verb.
If there are two coordinated subjects, the verb usually goes in plural.

With alternative subjects joined by o or u, the verb typically agrees with the nearest element: the professor or the director decide, the director or the professor decides, you or other classmates may enter. The verb form adapts to the last member of the group because that one remains closest to the verb. In formal registers, this nearby agreement is often avoided by reorganizing the sentence so the verb does not depend on such a visible choice. The alternative with o and u does not create a summed subject, but a choice between two possibilities.

el más cercanoevitar la cercana

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En este estilo se prefiere la concordancia plural general para mantener la oración más formalEn este registro la concordancia cercana hace que el verbo se ajuste al elemento final

Agreement with alternate subjects

Region	Variant	Definition	Example
Spain	el más cercano	In this register the near concordance makes the verb adjust to the final element.	O mi tía o mis vecinos traen churros.Or my aunt or my neighbors bring churros.
Mexico	evitar la cercana	In this style the general plural concordance is preferred to keep the sentence more formal.	O el piloto o las azafatas resuelven el problema.Or the pilot or the flight attendants resolve the problem.

Scramble

Collective expressions and quantities can require singular or plural depending on meaning. Most people agree presents the group as a unit; most of the students agree highlights the individuals in the set. Something similar happens with a group of tourists, a dozen of roses, half of the neighbors. The agreement depends on whether you think of the whole as a block or its members as individuals. Usage can vary by region and communicative intent.

singular colectivoplural por sentido

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Con una cantidad grande a veces se prefiere el plural cuando se piensa en los individuosCon un colectivo singular el verbo puede ir en singular cuando se ve como una unidad

Agreement with collectives and quantities

Region	Variant	Definition	Example
Spain	singular colectivo	With a singular collective the verb can be singular when viewed as a unit.	La multitud aplaude como una sola voz.The crowd applauds as a single voice.
Argentina	plural por sentido	With a large quantity sometimes the plural is preferred when thinking of the individuals.	Una docena de turistas buscan sombra en la playa.A dozen of tourists look for shade on the beach.

Scramble

The concordance helps to identify which word is the subject and which is the verbal nucleus. In the boys run, the verb in plural confirms that the boys is the subject. In the boy runs, the singular form of the verb signals that the boy is the subject, even if it appears after. It also helps detect confusions when there are several names near the verb: the verbal form is not chosen by proximity, but by the real subject. In sentences with subordinate clauses, this cue remains useful to separate internal relationships, as seen in Subordinate Clauses.

Agreement to recognize the subject

Idea
The verb helps identify the core of the subject.
Agreement allows separating subject and verb in the sentence.