Vamos a ensayar antes de la retransmisión.

Vamos a + infinitive is a very common way to talk about the near future in Spanish, like we’re going to rehearse.

So:

• Vamos a ensayar = We’re going to rehearse
• Ensayamos can mean we rehearse or we rehearsed, depending on context

Using vamos a ensayar makes the future meaning much clearer.

It is the structure ir a + infinitive:

• vamos = we go / we are going
• a = part of the future structure
• ensayar = to rehearse

Together, ir a + infinitive means to be going to do something.

Other examples:

• Voy a estudiar = I’m going to study
• Van a salir = They’re going to go out
• Vamos a empezar = We’re going to begin

Spanish often drops subject pronouns when they are not needed, because the verb ending already tells you who the subject is.

• vamos already tells you it means we
• So (nosotros) vamos a ensayar and vamos a ensayar mean the same thing

Including nosotros is possible, but it usually adds emphasis or contrast.

Normally, vamos a ensayar means we’re going to rehearse, not let’s rehearse.

For let’s..., Spanish often uses the nosotros command form:

• Ensayemos = Let’s rehearse

That said, in real conversation, vamos a + infinitive can sometimes sound a bit like a suggestion depending on tone and context, but its basic grammatical meaning is still we are going to....

Ensayar means to rehearse or to practise for a performance.

It is commonly used for things like:

• theatre
• music
• dance
• broadcasting
• presentations

So it is broader than just stage acting. In this sentence, it fits well with preparing before a broadcast.

Antes de means before.

In Spanish, antes is usually followed by de when what comes next is:

• a noun:
  antes de la retransmisión = before the broadcast
• an infinitive:
  antes de salir = before leaving

So here, because la retransmisión is a noun phrase, antes de is exactly what you need.

Because la retransmisión is feminine.

Spanish only contracts:

• de + el = del
• a + el = al

But with la, there is no contraction:

• de la retransmisión = correct
• del retransmisión = incorrect

Yes, retransmisión is a feminine noun, so it takes la.

Many Spanish nouns ending in -ción are feminine:

• la canción
• la información
• la retransmisión

So la retransmisión is the natural form.

These words can overlap, but there are slight differences:

• retransmisión = broadcast / relay / rebroadcast, often emphasising that something is being transmitted to an audience, sometimes live
• transmisión = transmission, a broader and more general word
• emisión = broadcast / airing, often used for TV, radio, or the act of broadcasting

In Spain, retransmisión is a very natural word for a sports event, concert, or other programme being broadcast.

The accent mark shows where the stress falls: retransmisión.

Without going too deeply into spelling rules, many words ending in -ión have a written accent because the stress falls on the final syllable:

• televisión
• información
• transmisión
• retransmisión

So the accent is both normal and necessary.

In Spain, a natural pronunciation would be roughly:

BA-mos a en-sa-YAR AN-tes de la re-trans-mi-SYON

A few useful points:

• vamos a is often said smoothly together
• ensayar is stressed on the last syllable: -yar
• retransmisión is stressed on the last syllable: -sión

In most of Spain, the s sounds are clear and distinct, and the final n in retransmisión is pronounced.

Yes, but it means something slightly different.

• antes de la retransmisión = before the broadcast
• antes de retransmitir = before broadcasting

The first uses a noun (the broadcast). The second uses an infinitive (to broadcast).

Both are grammatically correct, but they focus on different things.

In Spanish, using the article here is very natural:

• antes de la retransmisión

Spanish often uses the definite article in places where English may or may not use one. In this sentence, la retransmisión sounds complete and idiomatic, especially if everyone knows which broadcast is being referred to.

Without the article, antes de retransmisión would not sound natural.