Learn Hardcore Portuguese (Portugal): O transporte público na cidade está cheio hoje. - Public transport in the city is crowded today.

O transporte público = public transportation in general
Transporte público (without o) is possible but sounds more like a title, label, or very telegraphic style (e.g. in a sign or heading).

So O transporte público na cidade está cheio hoje sounds natural and complete in European Portuguese. Leaving out o in normal speech would sound a bit odd or “headline‑like.”

Why is it O transporte público and not A transporte pública? How do I know the gender?

Transporte is a masculine noun in Portuguese, so it takes:

article: o transporte
adjective: público (masculine singular)

You see the masculine gender:

in the article o
in the adjective ending -o in público

There isn’t a reliable rule to guess gender from the English word; you generally have to learn the gender with each noun:

o transporte (masc.)
a cidade (fem.)
o carro (masc.)
a estação (fem.)

Always learn nouns together with their article, e.g. o transporte, a cidade.

In Portugal I’ve often heard os transportes públicos instead. What’s the difference between o transporte público and os transportes públicos?

Both are correct, but the plural form is more common in Portugal in everyday speech:

Os transportes públicos na cidade estão cheios hoje.
(literally “The public transports in the city are full today.”)

Differences in nuance:

o transporte público (singular) – talking about the system as one whole thing
os transportes públicos (plural) – talking about the different modes: buses, trams, metro, etc.

In practice, many European Portuguese speakers naturally say os transportes públicos when they mean “public transport.” Your original sentence with the singular is still correct and understandable.

What exactly does na mean in na cidade?

Na is a contraction of:

em (in / on / at) + a (the, feminine singular)
→ em + a = na

So:

em a cidade → na cidade = in the city

Other similar contractions:

em + o = no → no carro (in the car)
em + os = nos → nos autocarros (on the buses)
em + as = nas → nas ruas (in the streets)

In natural Portuguese, you normally must use these contractions; saying em a cidade is incorrect in standard usage.

Can na cidade also mean “into the city” or does it only mean “in the city”?

Na cidade normally means “in the city” (location):

O transporte público na cidade está cheio hoje.
The public transport in the city is crowded today.

To express movement into the city, you’d usually use something like:

para a cidade – to / into the city
entrar na cidade – to enter the city (here na appears because of the verb “enter”)

So na cidade on its own is basically “in the city,” describing where something is.

Why is it está cheio and not é cheio?

Portuguese distinguishes two verbs for “to be”:

ser – used for permanent or defining characteristics
estar – used for temporary states or conditions

Here, being cheio (full / crowded) is a temporary situation, just for today:

O transporte público na cidade está cheio hoje.
→ It is crowded today (but not always).

If you said:

O transporte público é cheio.

That would sound like you’re saying it is inherently full all the time, which is strange or wrong in most contexts. For “crowded today,” you must use estar.

What does cheio literally mean, and why is it translated as “crowded”?

Literally, cheio means “full.”

O copo está cheio. – The glass is full.
A sala está cheia. – The room is full.

When talking about buses, trains, metro, etc., estar cheio is naturally understood as “to be crowded / packed with people.”

So:

O transporte público na cidade está cheio hoje.
literally: “public transport in the city is full today”
natural English: “public transport in the city is crowded today.”

The idea is the same: full of people.

Why is it cheio and not cheia or cheios?

Adjectives in Portuguese agree with the noun in gender (masculine/feminine) and number (singular/plural).

Here, the subject is:

O transporte público – masculine singular

So the adjective must also be:

masculine singular → cheio

Other forms would be:

cheia – feminine singular (e.g. a cidade está cheia)
cheios – masculine plural (e.g. os transportes públicos estão cheios)
cheias – feminine plural (e.g. as ruas estão cheias)

In your sentence, masculine singular cheio is required to match o transporte.

Could I say muito cheio or something stronger in European Portuguese?

Yes. Common intensifiers:

muito cheio – very full / very crowded
cheio de gente – full of people
a abarrotar (informal) – jam‑packed, absolutely crammed

Examples:

O transporte público na cidade está muito cheio hoje.
Os transportes públicos hoje estão cheios de gente.
Os transportes públicos estão a abarrotar hoje.

In European Portuguese, lotado is understood but sounds more Brazilian; cheio and a abarrotar are more typical in Portugal.

Why is the word order O transporte público na cidade está cheio hoje and not Hoje o transporte público na cidade está cheio?

Both orders are correct:

O transporte público na cidade está cheio hoje.
Hoje o transporte público na cidade está cheio.

Differences:

Putting hoje at the end is very common and neutral.
Putting hoje at the beginning gives more emphasis to “today”:
- Hoje o transporte público na cidade está cheio.
  → “Today, public transport in the city is crowded” (maybe contrasting with other days).

So you can move hoje quite freely:

Hoje o transporte público na cidade está cheio.
O transporte público na cidade hoje está cheio.
O transporte público na cidade está cheio hoje.

All are grammatical; the nuance is just about emphasis and style.

Is público an adjective or a noun here? And why does it come after transporte?

In this sentence, público is an adjective describing the noun transporte.

Word order:

Portuguese usually places adjectives after the noun:
- transporte público – public transport
- carro novo – new car
- cidade grande – big city

Adjectives before the noun also exist, but they tend to add a slightly different nuance or sound more literary. In this case, público transporte would sound wrong.

So the natural order is transporte público = “public transport.”

Why does público have an accent mark, and how do I pronounce it?

The accent in público shows:

Which syllable is stressed – PÚ-bli-co (stress on the first syllable)
That the vowel is open /u/ and that the word is not pronounced as if the stress were later.

Pronunciation (European Portuguese, approximate English-like guide):

pú – like “poo” but shorter, stressed: PU
bli – like “blee”
co – like “koo” (unvoiced c before o)

So roughly: PU-blee-koo.

Without the accent, the word would not follow normal stress rules and might be misread or ambiguous in writing; the accent clarifies both stress and pronunciation.

How do you pronounce cheio in European Portuguese?

In European Portuguese, cheio is pronounced roughly like “SHAY-oo” in two syllables:

ch → sh sound (like “sh” in “she”)
ei → similar to “ay” in “day”
final o → a weak “oo” sound, often very short

So a simple approximation:

cheio ≈ SHAY-oo

In fast speech, the second syllable can be quite reduced, something like “SHAY-u”.

The verb está is present tense. Does it include the idea of “right now,” like English “is being” or “is getting”?

Yes, the Portuguese presente do indicativo with estar can naturally refer to a current, temporary situation, very often meaning “right now / today / at the moment.”

O transporte público na cidade está cheio hoje.
→ Public transport is (right now) crowded today.

Portuguese doesn’t need a special continuous form (is being, is getting) here. Context words like hoje, agora, neste momento give the time frame:

O transporte público está cheio agora. – It’s crowded right now.
O transporte público está a ficar cheio. – It is getting full (here we use estar a + infinitive for “is getting / is becoming”).

Is it cidade or cidadE with a pronounced final “e”? How is cidade pronounced?

Cidade is pronounced in European Portuguese roughly like “see-DAH-d(ɨ)”:

ci → like “see”
da → “dah” (with a light d)
final de → a very weak, almost mute sound, like a very quick “d” plus a very short, reduced vowel (something like ɨ).

So a rough guide: see-DAHd (with a very light final sound). The e at the end is not pronounced as a full “eh” or “ee”, it’s reduced.