Mi vecina siempre quiere saludar a todo el mundo por la mañana.

Vecina is the feminine form of vecino. It tells you the neighbour is female. Spanish nouns that refer to people often change form to match gender:

• vecino = male neighbour
• vecina = female neighbour

So mi vecina means my female neighbour.

Because mi already works as a possessive determiner, like my in English. In Spanish, you normally do not use an article before a noun when you already have a possessive like mi, tu, su, nuestro.

So:

• mi vecina = correct
• la mi vecina = not standard modern Spanish

Because mi here is a possessive adjective meaning my. That word has no accent.

Compare:

• mi vecina = my neighbour
• mí = me / myself after a preposition, as in para mí

So the accent changes the function of the word.

Siempre is an adverb, and in Spanish adverbs like this often go before the conjugated verb.

So mi vecina siempre quiere... is a very natural word order.

You may hear other positions in some contexts, but this is the most neutral and common one here. Putting siempre before quiere makes it clear that always applies to the wanting.

After querer + another verb, Spanish normally uses the infinitive directly, with no extra preposition.

So:

• quiere saludar = correct
• quiere a saludar = incorrect

This is like:

• quiero comer
• quiere salir
• queremos hablar

Because quiere is the only conjugated verb in the sentence. After a verb like querer, the next verb stays in the infinitive.

Structure:

• quiere = conjugated verb, she wants
• saludar = infinitive, to greet

This is the same idea as English wants to greet.

This is the personal a. In Spanish, when the direct object is a person or a group of people, you usually put a before it.

Here, todo el mundo means everybody / everyone, so it refers to people. That is why you get:

• saludar a todo el mundo

The a does not mean to here. It is just the marker used with human direct objects.

Literally, yes, but in real usage it usually means everyone or everybody.

It is a fixed expression:

• todo el mundo = everyone / everybody

So even though the words look like all the world, you should usually understand it as a common way to refer to all people in general.

Grammatically, it is treated as singular, even though the meaning is plural in English.

That is why, if it were the subject, you would normally use a singular verb:

• Todo el mundo sabe eso = Everybody knows that

In your sentence, it is the object, so the verb does not change because of it.

Because todo el mundo is a fixed expression. Todo agrees with mundo, which is singular:

• todo
  • el mundo

You cannot say todos el mundo.

If you wanted a different expression, you could say something like a todos in the right context, but todo el mundo is the standard phrase for everyone.

In Spain, por la mañana is the normal way to say in the morning.

The same pattern is used with other parts of the day:

• por la mañana = in the morning
• por la tarde = in the afternoon/evening
• por la noche = at night / in the evening

En la mañana does exist, but it is less usual in Spain and may sound more regional or more marked. For a neutral Spain-Spanish sentence, por la mañana is the best choice.

Saludar means to greet, to say hello to, or to acknowledge politely when you meet someone.

So it is a bit broader than just saying hello. It can include any normal greeting behaviour.

Examples:

• Saludó a sus vecinos = He greeted his neighbours.
• Quiero saludar a Ana = I want to say hello to Ana.

Yes, but the meaning changes.

• quiere saludar = wants to greet
• saluda = greets

So:

• Mi vecina siempre quiere saludar... focuses on her desire or inclination.
• Mi vecina siempre saluda... states that she actually does it.

The first can suggest personality or intention; the second states the action more directly.

In most of Spain, the c before i is pronounced like th in thin.

So vecina sounds roughly like beh-THEE-na.

A few notes:

• v and b sound very similar in Spanish
• the stress is on ci: ve-CI-na
• in Latin America, many speakers would pronounce the c like an s, so it would sound more like beh-SEE-na

Yes. Spanish word order is flexible, especially with time expressions.

You could also hear:

• Por la mañana, mi vecina siempre quiere saludar a todo el mundo.
• Mi vecina, por la mañana, siempre quiere saludar a todo el mundo.

But the original order is very natural and neutral. Putting por la mañana at the end is a common, straightforward choice.