Hay trece estudiantes aquí.

Hay means there is or there are.

In this sentence, hay trece estudiantes aquí, it means there are thirteen students here.

Spanish uses the same word, hay, for both singular and plural:

• Hay un estudiante aquí = There is one student here.
• Hay trece estudiantes aquí = There are thirteen students here.

Use hay when you are saying that something exists or is present somewhere.

So:

• Hay trece estudiantes aquí = There are thirteen students here.

Use están when you are talking about the location of specific people or things that are already identified:

• Los estudiantes están aquí = The students are here.

A helpful contrast:

• Hay estudiantes aquí = There are students here.
• Los estudiantes están aquí = The students are here.

Because hay is an impersonal form of the verb haber. It does not agree with the noun that follows it.

So Spanish says:

• Hay un libro
• Hay dos libros
• Hay trece estudiantes

Even though estudiantes is plural, hay stays the same.

Hay comes from the verb haber.

In modern Spanish, haber is often used:

1. as a helping verb, as in he comido
2. in the impersonal existential form hay, meaning there is/there are

So hay is a special fixed form you should memorize as the standard way to say there is / there are in the present tense.

Spanish often does not use an article after hay when talking about the existence of something in a general way.

So:

• Hay trece estudiantes aquí = There are thirteen students here.

You would not normally say:

• Hay los trece estudiantes aquí for this meaning

That sounds wrong for an existential sentence. If you use a definite article like los, you usually switch to a different structure:

• Los trece estudiantes están aquí = The thirteen students are here.

Yes. That is completely natural.

Both are correct:

• Hay trece estudiantes aquí
• Aquí hay trece estudiantes

The difference is mostly one of emphasis:

• Hay trece estudiantes aquí emphasizes the existence/number first.
• Aquí hay trece estudiantes emphasizes the location first.

In everyday speech, both are common.

Spanish word order is often flexible. Putting aquí at the end is a very normal way to add the location after the main statement.

So:

• Hay trece estudiantes aquí = There are thirteen students here.

But you can also move it:

• Aquí hay trece estudiantes

Both sound natural. Spanish often places location words either at the beginning or end, depending on what the speaker wants to highlight.

Both can mean here, and in Latin America both are very common.

Very generally:

• aquí often sounds a little more specific, like right here
• acá can sound a little broader, like over here

So you may hear:

• Hay trece estudiantes aquí
• Hay trece estudiantes acá

In many situations, the difference is small, and either one is fine.

Hay is usually pronounced roughly like the English word eye, but with an h that is silent.

So:

• h = silent
• ay sounds like eye

That gives hay a pronunciation close to eye.

Be careful not to pronounce the h.

The accent mark in aquí shows which syllable is stressed.

It is pronounced a-QUÍ, with the stress on the last syllable.

Without the accent mark, Spanish spelling rules would suggest a different stress pattern, so the written accent is necessary.

Estudiantes can be masculine, feminine, or mixed, depending on who the students are.

It is a noun ending in -ante, and nouns of this type are often the same for both genders:

• el estudiante = the male student
• la estudiante = the female student

In the plural:

• los estudiantes can mean male students or a mixed group
• las estudiantes means all female students

In your sentence, there is no article, so estudiantes by itself does not show gender.

Trece is the normal form of thirteen, and it does not change for gender.

So you say:

• trece estudiantes
• trece libros
• trece mesas

Many Spanish numbers stay the same no matter what noun follows. A few numbers do change in certain situations, especially uno:

• un estudiante
• una estudiante

But trece does not change.

Yes, often you can, but there is a slight difference in tone and usage.

• estudiantes = students
• alumnos = students, often in the sense of pupils or enrolled learners

In many contexts, both work:

• Hay trece estudiantes aquí
• Hay trece alumnos aquí

In much of Latin America, estudiante is very common and neutral.

Yes, if the location is already understood from context.

Then you can simply say:

• Hay trece estudiantes

That means There are thirteen students.

Adding aquí makes the location explicit:

• Hay trece estudiantes aquí = There are thirteen students here.

It is neutral and works in both formal and informal situations.

Hay trece estudiantes aquí is a standard, natural sentence that you could use:

• in conversation
• in class
• in a report
• in a presentation

Nothing in the sentence is especially casual or especially formal.