La madre viste al niño.

Because Spanish often uses the personal a before a specific human direct object.

Here, el niño is the person receiving the action of vestir. So Spanish adds a:

• La madre viste a el niño → this contracts to La madre viste al niño

So al here is just a + el.

Important: in this sentence, a does not mean to. It is just marking the boy/the child as a person who is the direct object.

Here, viste is the third-person singular present tense of vestir.

That means it matches:

• la madre
• ella
• usted

So:

• La madre viste al niño = The mother dresses the child / is dressing the child

Because vestir is a stem-changing verb.

In the present tense, the e in the stem changes to i in most forms:

• yo visto
• tú vistes
• él/ella/usted viste
• nosotros vestimos
• ellos/ellas/ustedes visten

So viste is the expected form.

This is a common pattern with verbs like:

• pedir → pide
• servir → sirve
• repetir → repite

Yes. Viste can also be the preterite tú-form of ver:

• tú viste = you saw

But in this sentence, that is not what it means.

Why not?

• The subject is La madre, so we need a verb form that matches she/the mother
• viste here clearly works as she dresses
• The rest of the sentence, al niño, also fits vestir a alguien = to dress someone

So context tells you this viste comes from vestir, not ver.

This is a very common question.

• vestir a alguien = to dress someone
• vestirse = to get dressed / to dress oneself

So:

• La madre viste al niño = The mother dresses the child
• El niño se viste = The child gets dressed

The se changes the meaning from doing the action to someone else to doing it to oneself.

Because Spanish normally uses an article with a common noun when it is acting as a regular noun phrase.

So:

• la madre = the mother

Using just madre would usually sound incomplete in a sentence like this, unless you were directly addressing someone:

• Madre, ven = Mother, come

You could also use a possessive:

• Mi madre viste al niño = My mother dresses the child

It can mean either, depending on context.

Most literally, niño means:

• boy
• young child
• kid

If the meaning shown to the learner is child, that is perfectly reasonable in many contexts. If the context makes gender important, then niño would usually be understood as boy.

Related words:

• niña = girl
• niños = children or boys, depending on context

The ñ is pronounced like ny in canyon.

A rough English approximation is:

• NEE-nyo

So:

• niño ≈ NEE-nyo

Also, ñ is its own letter in Spanish. It is not just n with an accent.

Yes.

In Spanish, the simple present can cover both:

• a general/habitual action
• an action happening now, depending on context

So La madre viste al niño can mean:

• The mother dresses the child
• The mother is dressing the child

If you want to make the right now meaning more explicit, you can say:

• La madre está vistiendo al niño

In Latin American Spanish, that progressive form is common when you want to emphasize that the action is in progress.

Yes, but La madre viste al niño is the most neutral and standard order.

It follows the common pattern:

• Subject + Verb + Object

You may sometimes see the object moved for emphasis:

• Al niño lo viste la madre

That is grammatical, but it is more advanced and more marked in style. Notice that Spanish usually adds lo when the direct object is moved to the front.

For learners, the basic version is the best one to use:

• La madre viste al niño