Learn Hardcore Spanish (Latin America): Por favor, trae tu identificación; sin ella no podrás entrar. - Please bring your ID; without it you won’t be able to enter.

Trae tu identificación = (You) bring your ID.
Traes is the present indicative (you bring / you are bringing), not a command.
Traiga is the formal command for usted.

Quick pattern (regular verbs):

Present él/ella: habla / come / vive
Affirmative tú command: habla / come / vive (same form)

For traer, 3rd person present is trae, so the tú command is also trae.

Why is it tu identificación and not tú identificación?

Because tu (without accent) is a possessive adjective: tu = your.

tu identificación = your ID

Tú (with accent) is the subject pronoun: tú = you.

Compare:

Tú tienes que traer tu identificación.
= You have to bring your ID.

Why is there no article, like la identificación or una identificación?

In Spanish, you normally don’t use an article after a possessive adjective such as mi, tu, su, nuestro, etc.

Correct: tu identificación
Incorrect: ~la tu identificación~ / ~una tu identificación~

So:

tu identificación = your ID (natural)
If you add more info, you still skip the article:
tu identificación de estudiante = your student ID

What’s the difference between traer and llevar here?

Both relate to moving something, but:

traer = bring towards the place where the speaker (or reference point) is.
llevar = take away from where the speaker is, or to some other place.

In this sentence, the idea is: bring your ID to the place where you need to enter, so traer is natural.

In many parts of Latin America, people sometimes use them more loosely, but the general rule is:

If you’re bringing it here/to the event: traer
If you’re taking it there/from here: llevar

What does sin ella refer to, and why is it feminine?

Ella here is a pronoun that replaces la identificación.

identificación is grammatically feminine (it ends in -ción and takes la).
So the pronoun that replaces it must also be feminine singular: ella.

You could repeat the noun:

…sin identificación no podrás entrar.

But it’s more natural and less repetitive to say:

…sin ella no podrás entrar.
= without it you won’t be able to enter.

Why is it no podrás entrar and not no puedes entrar?

Both are possible, but they have slightly different nuances:

no puedes entrar = you can’t enter (present, more immediate/flat)
no podrás entrar = you won’t be able to enter (future, more like a warning or consequence)

Using the future for rules or consequences is very common in Spanish to sound more definite:

Si no traes tu identificación, no podrás entrar.
If you don’t bring your ID, you will not be able to get in.

It emphasizes that this is a fixed rule or inevitable result, not just a present inability.

Could I change the word order, like Sin ella no podrás entrar vs No podrás entrar sin ella?

Yes, both are correct and common:

Sin ella no podrás entrar.
No podrás entrar sin ella.

The meaning is the same: Without it, you won’t be able to enter.

Placing sin ella at the beginning can slightly emphasize the condition (“without it”), but it’s a very subtle difference. Spanish allows relatively flexible word order here.

Why is there a semicolon (;) instead of a comma or a period?

The semicolon in Spanish works very similarly to English:

It joins two related but independent clauses:
- Por favor, trae tu identificación;
- sin ella no podrás entrar.

You could also write:

Por favor, trae tu identificación. Sin ella no podrás entrar.

or (less ideal in formal writing):

Por favor, trae tu identificación, sin ella no podrás entrar.

The semicolon nicely shows that the second part explains the reason/consequence of the first.

Is this sentence formal or informal? How would I say it formally?

This sentence is informal because it uses the tú command:

trae (tú)
tu identificación

For a formal version (for usted):

Por favor, traiga su identificación; sin ella no podrá entrar.

Changes:

trae → traiga (formal command)
tu → su (formal “your”)
podrás → podrá (3rd person, matching usted)

Why do identificación and podrás have accent marks?

Accent marks in Spanish show where the stress falls when it doesn’t follow the normal rules.

identificación
- Ends in -n, so normally stress would be on the second-to-last syllable.
- But the stress is on the last syllable: i-den-ti-fi-ca-CIÓN.
- So it needs an accent: identificación.
podrás (from poder)
- Ends in -s, so normally stress would be on the second-to-last syllable.
- But we stress the last syllable: po-DRÁS.
- So it takes an accent: podrás.

These accents change pronunciation and, in some cases, meaning, so they’re important to keep.