Mi vecino chileno llega mañana.

Mi without an accent is the possessive adjective meaning my.

• mi vecino = my neighbour
• mí with an accent is a pronoun meaning me after a preposition:
  • para mí = for me
  • sin mí = without me

So in this sentence, mi is correct because it shows possession.

Vecino usually means neighbour.

In Spain, it can also sometimes refer more broadly to someone who lives nearby, but in a sentence like Mi vecino chileno llega mañana, the most natural meaning is my Chilean neighbour.

It comes from the noun vecino:

• el vecino = the male neighbour
• la vecina = the female neighbour

Because chileno is describing vecino. It is an adjective meaning Chilean.

In Spanish, adjectives often come after the noun:

• vecino chileno = Chilean neighbour
• coche rojo = red car

So:

• vecino = neighbour
• chileno = Chilean

Together, vecino chileno means Chilean neighbour.

In Spanish, nationalities and languages are normally not capitalised.

So Spanish writes:

• chileno = Chilean
• español = Spanish
• inglés = English

This is different from English, where Chilean, Spanish, and English are capitalised.

Spanish often uses the present tense to talk about the near future, especially when there is a clear time expression like mañana.

So:

• llega mañana = he/she is arriving tomorrow / arrives tomorrow

This is very natural Spanish.

You could also say:

• Mi vecino chileno llegará mañana

That uses the simple future (will arrive), but llega mañana is extremely common and natural.

Llega is the third person singular present tense of llegar.

Conjugation:

• yo llego = I arrive
• tú llegas = you arrive
• él / ella / usted llega = he / she / you (formal) arrive(s)

In the sentence, the subject is Mi vecino chileno, which is he, so Spanish uses llega.

Because Spanish normally does not use an article before a possessive adjective like mi, tu, su, etc.

So you say:

• mi vecino = my neighbour
• tu casa = your house
• su coche = his/her/their car

Not:

• el mi vecino ✘

The possessive already makes it definite enough.

It can mean either, depending on context.

• mañana = tomorrow
• la mañana = the morning / morning

In Mi vecino chileno llega mañana, it clearly means tomorrow, because it is being used as a time word with the verb llega.

Compare:

• Llega mañana = He arrives tomorrow.
• Llega por la mañana = He arrives in the morning.

You would change the words to the feminine forms:

• Mi vecina chilena llega mañana.

Changes:

• vecino → vecina
• chileno → chilena

The adjective must agree with the noun in gender and number.

You would make the noun, adjective, and verb plural:

• Mis vecinos chilenos llegan mañana. = My Chilean neighbours arrive tomorrow.

Changes:

• mi → mis
• vecino → vecinos
• chileno → chilenos
• llega → llegan

If they were all women:

• Mis vecinas chilenas llegan mañana.

A simple Spain pronunciation guide would be:

• Mi = mee
• vecino = roughly beh-THEE-no in much of Spain
• chileno = roughly chee-LEH-no
• llega = roughly YEH-ga in most modern accents
• mañana = ma-NYA-na

A few useful pronunciation points for Spain Spanish:

• c before i in vecino is often pronounced like th in thin in much of Spain.
• ll in llega is usually pronounced like a y sound.
• ñ in mañana sounds like ny in canyon.

Yes, you could, but it is less compact and not the most usual version here.

• Mi vecino chileno = my Chilean neighbour
• Mi vecino de Chile = my neighbour from Chile

Both are understandable. The adjective chileno is the more direct and natural choice in this sentence.

The sentence follows a very normal Spanish pattern:

subject + verb + time expression

• Mi vecino chileno = subject
• llega = verb
• mañana = time expression

So:

• Mi vecino chileno llega mañana.

This is straightforward, neutral word order in Spanish.