El hijo de mi vecina va al colegio a pie.

El means the. It is the masculine singular definite article, and it matches hijo, which is a masculine singular noun.

• el hijo = the son
• If it were a daughter, it would be la hija = the daughter

Spanish articles usually have to agree in gender and number with the noun.

Because hijo means son, while hija means daughter.

• el hijo = the son
• la hija = the daughter

The ending -o is often masculine and -a is often feminine, though that is a general pattern, not an absolute rule.

Spanish does not use an apostrophe + s to show possession. Instead, it usually uses de.

So:

• el hijo de mi vecina = my neighbor’s son
• literally: the son of my female neighbor

This structure is extremely common in Spanish:

• el coche de Juan = Juan’s car
• la hermana de Ana = Ana’s sister

Because vecina refers to a female neighbor. Spanish nouns often change form depending on gender:

• vecino = male neighbor
• vecina = female neighbor

So mi vecina means my female neighbor.

If the neighbor were male, the sentence would be:

• El hijo de mi vecino va al colegio a pie.

In modern standard Spanish, possessives like mi, tu, su, nuestro, etc. normally go directly before the noun, without an article.

So you say:

• mi vecina = my neighbor
• mi casa = my house

Not normally:

• la mi vecina ❌

That older structure exists in some historical or regional uses, but it is not standard everyday Spanish.

Va is the third-person singular form of the verb ir (to go) in the present tense.

Conjugation of ir in the present:

• yo voy = I go
• tú vas = you go
• él/ella va = he/she goes
• nosotros vamos = we go
• vosotros vais = you all go
• ellos/ellas van = they go

Since el hijo is he, the sentence uses va.

Because the verb ir usually takes the preposition a when expressing destination:

• ir a
  • place = to go to a place

So:

• va a el colegio = he goes to the school

But a + el contracts to al, which gives:

• va al colegio

You cannot usually leave out a here.

Because in Spanish, a + el contracts to al.

• a + el = al
• de + el = del

Examples:

• Voy al mercado. = I go to the market.
• Viene del trabajo. = He/She comes from work.

Important: this contraction does not happen with la:

• Voy a la playa. = I go to the beach.
  Not ala ❌

No. In Spain, colegio usually means school, especially a primary or sometimes general school context, not college in the English sense.

This is a very common false friend for English speakers.

Depending on context:

• colegio = school
• universidad = university
• instituto = secondary school / high school (in Spain)

So va al colegio means he goes to school, not he goes to college.

Spanish often uses the definite article with places and institutions where English may leave it out.

So Spanish says:

• va al colegio
• literally: goes to the school

But in natural English, we usually say:

• goes to school

This is one of those places where Spanish and English structure things differently.

A pie means on foot or walking.

It is a fixed expression:

• ir a pie = to go on foot
• volver a pie = to come back on foot

Examples:

• Voy al trabajo a pie. = I go to work on foot.
• Está a diez minutos a pie. = It’s ten minutes away on foot.

Because a pie is an idiomatic expression. The first a in va al colegio marks destination (to school), while the second a is part of the expression a pie (on foot).

So the sentence has:

• va al colegio = goes to school
• a pie = on foot

They are doing different jobs.

Yes, but it is not exactly the same in emphasis.

• Va al colegio a pie = He goes to school on foot.
• Camina al colegio = He walks to school.

Both are natural, but ir ... a pie focuses on the means of going, while caminar focuses more directly on the action of walking.

This is the normal, neutral Spanish word order:

• El hijo de mi vecina = subject
• va = verb
• al colegio = destination
• a pie = manner / means

Spanish word order is often flexible, but this version sounds natural and straightforward.

You could move things around for emphasis, for example:

• El hijo de mi vecina va a pie al colegio.

This is also possible, though the original sentence is very standard.

Yes. De has many uses in Spanish, but here it clearly marks a relationship similar to possession or belonging.

In this sentence:

• el hijo de mi vecina = the son of my neighbor / my neighbor’s son

In other contexts, de can mean things like:

• from
• of
• made of
• about

But here the possession/family-relationship meaning is the relevant one.

They could absolutely just say Va al colegio a pie if the subject is already clear from context.

Spanish often leaves out subject pronouns, and sometimes even longer subjects are omitted when understood.

But in this sentence, El hijo de mi vecina is included because the speaker wants to identify exactly who they are talking about.

You could say:

• Él va al colegio a pie. = He goes to school on foot.

However, Spanish often drops subject pronouns unless needed for emphasis or clarity, so the more natural short version is often:

• Va al colegio a pie.

The full noun phrase El hijo de mi vecina is useful when introducing or identifying the person.