Si la cantant perd el micròfon, l'actor li'n portarà un altre des del costat de l'escenari.

In Catalan, a real or likely condition normally uses present indicative after si.

So the pattern is:

Si + present, future

That is exactly what you have here:

Si la cantant perd el micròfon, l'actor li'n portarà un altre.

English often does something similar: If she loses it, he will bring another one.

Catalan does not normally use the future after si in this kind of sentence.

Not in this sentence.

Here, si introduces a normal, open condition, so Catalan uses the indicative:

Si la cantant perd...

If you wanted a more hypothetical or unreal idea, then Catalan would use a different pattern, for example:

Si la cantant perdés el micròfon, l'actor li'n portaria un altre.

So:

• real/possible condition → si + indicative
• hypothetical/unreal condition → often si + imperfect subjunctive, with conditional in the main clause

cantant is a common-gender noun. That means the noun form stays the same, and the article shows the gender:

• el cantant = the male singer
• la cantant = the female singer

So cantant itself does not change here.

This is different from nouns like actor, which has a distinct feminine form:

• actor
• actriu

Because li is an indirect object pronoun, and it means to him / to her.

It does not change for gender in the singular.

Here, the singer is the person receiving the new microphone, so Catalan uses li:

l'actor li'n portarà un altre
= the actor will bring her another one

If you used la, that would be a direct object pronoun, not the right role here.

So the distinction is grammatical, not based on natural gender:

• li = to him / to her
• la = her, as a direct object

li'n is made of two clitic pronouns:

• li = to her / to him
• en = of it / one of them / some

Together, in this sentence, they mean something like:

to her ... one of those

So:

li'n portarà un altre

means that the actor will bring her another one.

English does not have an exact one-word equivalent for en, so this structure often feels unusual to English speakers at first.

It refers back to el micròfon.

Catalan often uses en when a noun is not repeated, especially with words like:

• un
• dos
• cap
• molts
• un altre

So instead of repeating micròfon, Catalan uses en:

• portarà un altre micròfon
• li'n portarà un altre

That n' is what makes un altre mean another one rather than leaving the noun completely vague.

In normal modern Catalan, un altre is the usual way to say another one.

So:

• un altre = another one
• una altra = another one, feminine

It is masculine here because it refers back to el micròfon, which is masculine.

If the missing noun were feminine, the form would change:

• una altra

So the agreement is with the omitted noun, not with cantant.

Because li'n are clitic pronouns, and with a finite verb in Catalan, clitics normally go before the verb:

li'n portarà

This is very normal Catalan word order.

They go after the verb in some other contexts, especially:

• affirmative commands: porta-li'n
• infinitives: portar-li'n
• gerunds: portant-li'n

So in this sentence, before the verb is exactly what you should expect.

There are two different things happening.

First, the article el / la often apostrophizes before a vowel sound:

• l'actor
• l'escenari

That is just the usual shortening of the article.

Second, in li'n, the pronoun en becomes 'n when attached in this combination:

• li + en → li'n

So the apostrophe is showing a shortened written form.

You also have a contraction in:

des del

because:

des de + el → des del

Literally, it means:

from the side of the stage

Breaking it down:

• des de = from
• des del = from the
• costat de = side of / beside
• l'escenari = the stage

So the phrase gives the point of origin: the actor will bring another microphone from the side of the stage.

Depending on context, English might also phrase it as from beside the stage.

You know it from the sentence structure and the context.

The subject of portarà is l'actor, so he is the one doing the action.

That makes li the recipient of the action, and the obvious recipient already mentioned is la cantant.

So:

• l'actor = the one who brings it
• li = the person he brings it to
• la cantant = the intended referent

Since li can mean to him or to her, context is what tells you which one is meant.

The accent shows both stress and vowel quality.

micròfon is stressed on the middle syllable:

mi-CRÒ-fon

The grave accent on ò tells you that this syllable is stressed and that the vowel is an open o.

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