O diretor disse que ninguém deve entrar no refeitório com as mãos sujas de giz.

Portuguese uses definite articles much more often than English. O diretor means the director/headmaster/principal, referring to a specific person that speaker and listener can identify.

In English, we often drop the in some contexts, but in Portuguese the article sounds natural here.

Disse is the preterite form of dizer — to say / to tell. So o diretor disse means the director said.

It is irregular, so you just have to learn it as a form:

• dizer → disse

Also, dizer que is the normal way to report what someone said:

• Ele disse que... = He said that...

Because Portuguese does not always shift the tense back the way English often does.

Here, the director spoke in the past — disse — but the rule is still valid now, so Portuguese keeps the present:

• disse que ninguém deve entrar...

In English, we often say said that nobody should enter..., but Portuguese can keep the present idea if the statement is still true or still applies.

Because ninguém already has a negative meaning: nobody / no one.

When a negative word like ninguém comes before the verb, Portuguese normally does not add não:

• Ninguém deve entrar. = Nobody should enter.

But if ninguém comes after the verb, then não is needed:

• Não vi ninguém. = I didn’t see anybody.

Because ninguém is grammatically singular, even though it refers to no people at all.

So it takes a singular verb:

• ninguém deve
• not ninguém devem

This is similar to English nobody is, not nobody are.

It can suggest either must or should, depending on context.

In this sentence, it expresses a rule or obligation, so English could translate it as:

• should not enter
• must not enter
• is not supposed to enter

The exact strength depends on tone and situation. In a school rule, it often feels fairly strong.

Because no is a contraction of em + o:

• em o → no

With entrar, Portuguese usually uses a preposition where English often does not:

• entrar no refeitório = enter the dining hall / go into the cafeteria

So even though English says enter the cafeteria, Portuguese says more literally enter into the cafeteria.

Refeitório is a dining hall, canteen, or cafeteria, especially in a school, workplace, or institution.

In Portugal, it sounds quite normal in institutional contexts. In a school sentence like this, refeitório is a very natural word.

Portuguese often uses the definite article with body parts instead of a possessive.

So:

• com as mãos sujas = with dirty hands

The possessive suas is not necessary because it is obvious whose hands are being talked about. If you said com as suas mãos, it would sound more emphatic or contrastive.

Because it agrees with mãos.

• mão is feminine
• mãos is plural

So the adjective must also be feminine plural:

• mãos sujas

Compare:

• a mão suja = the dirty hand
• as mãos sujas = the dirty hands

Because sujo de is a very common Portuguese pattern meaning dirty with / stained with / covered in something.

So:

• mãos sujas de giz = hands dirty with chalk

If you said com giz, it could sound more like with chalk in the sense of having chalk or using chalk, not necessarily stained by it.

In European Portuguese, giz is pronounced with a final sound like sh:

• giz ≈ geesh (very approximate)

A few other tricky words here are:

• ninguém — ends with a nasal sound
• mãos — also has a nasal vowel/diphthong
• refeitório — stress on tó

If you are learning European Portuguese, the nasal sounds in ninguém and mãos are especially important to notice.