Tus mensajes me animan cuando estoy nerviosa antes de hablar en público.

Because mensajes is plural.

• tu = your, for one thing
• tus = your, for more than one thing

So:

• tu mensaje = your message
• tus mensajes = your messages

Because the subject is Tus mensajes, which is third person plural.

The verb animar in the present tense changes like this:

• yo animo
• tú animas
• él/ella/usted anima
• ellos/ellas/ustedes animan

Since mensajes is plural, Spanish uses animan.

Me is the object pronoun meaning me.

In Tus mensajes me animan, the messages are affecting me:

• Tus mensajes = the thing doing the action
• me = the person receiving the action
• animan = encourage / cheer up

So the basic structure is:

Your messages encourage me.

Spanish usually uses estar for temporary states and feelings, and ser for more permanent characteristics.

So:

• estoy nerviosa = I am nervous right now / in this situation
• soy nerviosa = I am a nervous person by nature

Here the speaker is talking about a temporary feeling before speaking in public, so estoy is the natural choice.

Because the adjective agrees with the speaker’s gender.

• A female speaker says nerviosa
• A male speaker says nervioso

So if a man were saying this sentence, it would be:

Tus mensajes me animan cuando estoy nervioso antes de hablar en público.

Because Spanish often leaves out subject pronouns when they are already clear from the verb form.

Estoy already means I am, so yo is not necessary.

You could say:

Tus mensajes me animan cuando yo estoy nerviosa...

but it usually sounds more natural without yo unless you want extra emphasis or contrast.

After antes, Spanish normally uses de + infinitive when the subject is the same.

Here, the person who is nervous is also the person who will speak, so Spanish uses:

• antes de hablar = before speaking

This is a very common pattern:

• antes de salir = before leaving
• antes de comer = before eating
• antes de dormir = before sleeping

If the subject changes, Spanish often uses antes de que + subjunctive instead.

En público is a fixed expression meaning in public.

So hablar en público means to speak in public or to do public speaking.

It is a very common phrase in Spanish, including in Spain.

Because after antes de, Spanish uses the infinitive when no new subject is introduced.

So:

• antes de hablar = before speaking
• antes de estudiar = before studying
• antes de empezar = before starting

English often uses before + -ing, but Spanish uses antes de + infinitive.

Because the sentence describes a repeated or usual situation.

It means something like:

• whenever I am nervous before speaking in public
• when I get nervous before speaking in public

Spanish often uses the present tense for this kind of general or habitual idea.

So cuando estoy nerviosa does not have to mean only at this exact moment. It can mean in those situations, whenever they happen.

It can mean either, depending on context.

In this sentence, me animan suggests that the messages give the speaker emotional support. In English, that could be:

• encourage me
• cheer me up
• boost my spirits

Here, encourage me is probably the best fit if the context is confidence before public speaking, but cheer me up is also close in feeling.

Yes, Spanish word order is more flexible than English.

The neutral order here is:

Tus mensajes me animan cuando estoy nerviosa antes de hablar en público.

But Spanish could also say:

Me animan tus mensajes cuando estoy nerviosa antes de hablar en público.

That version puts a little more focus on me animan or sounds slightly more expressive. The original sentence is the most straightforward and neutral.

Not if you want the same meaning.

• antes de hablar en público = before speaking in public
• al hablar en público = when speaking in public / while speaking in public

So antes de talks about the time before the action, while al talks about the moment during the action or the general act itself.

In this sentence, antes de hablar en público is correct because the nervousness happens beforehand.