Isto é suficiente.

A word-by-word breakdown is:

• Isto = this
• é = is
• suficiente = sufficient / enough

So the structure is very close to English: this is sufficient.

Both isto and isso can refer to this/that, but traditionally they are used a little differently:

• isto = something close to the speaker, or something not yet specified
• isso = something close to the listener, or something already mentioned

In modern Brazilian Portuguese, though, this distinction is often weakened in everyday speech, and isso is much more common than isto.

So while Isto é suficiente is correct, in real conversation many Brazilians would more naturally say:

• Isso é suficiente.

Yes, it is grammatical and perfectly understandable.

However, in everyday Brazilian Portuguese, isso is usually more common than isto, so:

• Isto é suficiente. = correct, slightly more careful or formal-sounding
• Isso é suficiente. = very common and natural in speech

So the sentence is fine, but it may sound a bit more textbook-like than the version with isso.

The accent marks both stress and meaning.

• é = is (from the verb ser)
• e = and

So the accent is important because it distinguishes two different words:

• é = verb
• e = conjunction

Without the accent, the meaning would change.

A simple approximation for English speakers is:

• Isto ≈ EES-too
• é ≈ eh
• suficiente ≈ soo-fee-see-EN-chee in much of Brazil

A more helpful pronunciation note:

• is in isto often sounds like ees
• final -te in Brazilian Portuguese often sounds like chee in many accents, especially after t before i/e
• the stressed syllable in suficiente is en: su-fi-ci-EN-te

So roughly: EES-too eh soo-fee-see-EN-chee

Pronunciation varies by region, but this is a good Brazilian-style approximation.

Yes. In this sentence, suficiente is an adjective.

It describes isto:

• Isto = the thing being talked about
• é suficiente = is sufficient / is enough

So the sentence structure is:

• subject: isto
• verb: é
• adjective: suficiente

No. Suficiente has the same form for both masculine and feminine singular.

Examples:

• O dinheiro é suficiente. = The money is enough.
• A quantia é suficiente. = The amount is enough.

For the plural, it does change:

• singular: suficiente
• plural: suficientes

Examples:

• Os recursos são suficientes.
• As informações são suficientes.

Yes. In many contexts, suficiente can correspond to enough in English.

For example:

• Isso é suficiente. = That is enough.
• Não é suficiente. = It is not enough.

Portuguese often uses suficiente where English might prefer either sufficient or enough, depending on style.

Yes. Isso é o suficiente is also correct, but it is slightly different.

Compare:

• Isso é suficiente. = That is sufficient / That is enough.
• Isso é o suficiente. = That is what is enough / That is the necessary amount.

O suficiente literally means the sufficient amount or enough as a noun phrase.

For example:

• Já é suficiente. = It is enough already.
• Já é o suficiente. = It is enough / It is the necessary amount.

Both are common, but o suficiente feels a bit more specific or emphatic.

No. In standard Portuguese, you need the verb é here.

So:

• Isto é suficiente. = correct
• Isto suficiente. = incorrect

Unlike some languages that omit to be in the present tense, Portuguese normally requires it in sentences like this.

Yes, a very common alternative is:

• Isso basta.

Here, bastar is a verb meaning to be enough / to suffice.

So you can compare:

• Isso é suficiente. = That is sufficient.
• Isso basta. = That’s enough / That suffices.

In everyday speech, basta is often more direct and natural in certain situations.

They are close in meaning, but the structure is different:

• Isto é suficiente uses ser + adjective
• Isso basta uses the verb bastar

Tone-wise:

• Isto é suficiente can sound a bit more formal or descriptive
• Isso basta can sound more direct and practical

For example:

• If you are evaluating something, Isso é suficiente fits well.
• If you want to say that’s enough, no more is needed, Isso basta is often very natural.

You should definitely recognize isto, but for everyday Brazilian Portuguese, isso is usually more important.

A practical rule for learners:

• understand isto
• be ready to hear it in writing, formal speech, or careful language
• use isso more often in conversation unless you have a specific reason to choose isto

So Isto é suficiente is correct, but Isso é suficiente is probably the version you will hear more often in Brazil.