A Maria não gosta de couve-flor.

In European Portuguese, it is very common to use the definite article before a person's first name: a Maria, o João, and so on.

So A Maria não gosta de couve-flor does not mean the Maria in a strange English sense. It is just normal Portuguese usage.

This is especially common in Portugal in everyday speech, and it also appears a lot in writing.

Yes. That is also grammatical.

But in European Portuguese, leaving the article out can sound more formal, more literary, or less conversational. If you are learning Portuguese from Portugal, using a/o before first names is a good default in everyday language.

Because Portuguese normally makes a sentence negative by putting não directly before the conjugated verb.

So:

• gosta = likes
• não gosta = does not like / doesn't like

Unlike English, Portuguese does not need an extra verb like does here.

Because gosta is the 3rd person singular form of the verb gostar in the present tense, and the subject is A Maria, which is singular.

Present tense of gostar:

• eu gosto
• tu gostas
• ele/ela/você gosta
• nós gostamos
• vocês/eles/elas gostam

So:

• A Maria gosta = Maria likes
• A Maria não gosta = Maria does not like

Because gostar normally takes the preposition de.

So the pattern is:

gostar de + noun/pronoun

Examples:

• gostar de música
• gostar de café
• gostar de couve-flor

This is different from English, where like takes a direct object with no preposition.

So A Maria não gosta de couve-flor is correct, but A Maria não gosta couve-flor is not standard Portuguese.

Here, couve-flor is being used in a general sense: cauliflower as a food in general.

After gostar de, Portuguese often uses a bare noun for general tastes and preferences:

• Gosto de café.
• Não gosto de peixe.
• Ela gosta de chocolate.

So não gosta de couve-flor means she does not like cauliflower in general.

If you say não gosta da couve-flor, that usually sounds more specific: a particular cauliflower, a particular dish, or something already known from the context.

Also remember:

• de + a = da

So da couve-flor is just a contraction of de a couve-flor.

Normally, it describes a general preference:

Maria doesn't like cauliflower.

That is the most natural reading of the present tense here.

If the speaker meant a one-time reaction, the context would usually make that clear. But with gostar / não gostar, the present tense very often expresses a general like or dislike.

Yes. It is feminine:

• a couve-flor
• a couve-flor fresca

In your sentence, you do not see the article because the noun comes after de in a general sense: de couve-flor.

So even though the word is feminine, the sentence does not show a before it.

Because couve-flor is a fixed compound noun, and its standard spelling uses a hyphen.

So the correct spelling is:

couve-flor

not couve flor as two separate words.

You would say:

Ela não gosta de couve-flor.

That means She doesn't like cauliflower.

Portuguese often leaves out subject pronouns when the subject is already clear from context, so in conversation you may also hear:

Não gosta de couve-flor.

But ela is perfectly correct when you want to state the subject clearly.

The important thing is that não has a nasal sound. The ending -ão is not pronounced like ordinary English ow.

A rough approximation is something like now, but with a nasal quality. That is only approximate, though.

If you use IPA, não is typically pronounced:

[nɐ̃w]

For many English speakers, the hardest part is making the vowel nasal rather than fully oral.