Этот перевод нужно подтвердить.

Because перевод is a masculine noun in Russian.

The demonstrative этот has to agree with the noun in gender, number, and case:

• этот = masculine
• эта = feminine
• это = neuter
• эти = plural

Since перевод is masculine singular, the correct form is этот перевод.

It is in the accusative case, because it is the thing being confirmed.

The verb подтвердить takes a direct object, and direct objects are usually in the accusative.

However, for inanimate masculine nouns, the accusative looks exactly like the nominative:

• nominative: этот перевод
• accusative: этот перевод

So even though the form looks like the subject form, its role in the sentence is the object.

Because this is an impersonal sentence.

Russian often uses structures like:

• нужно сделать
• надо проверить
• можно войти

These do not need an explicit subject like someone or it.

So Этот перевод нужно подтвердить literally works like:

• This translation — it is necessary to confirm

Natural English usually adds a subject:

• This translation needs to be confirmed
• We need to confirm this translation
• This translation must be confirmed

Нужно means necessary, needed, or must/need to, depending on how you translate it.

In this sentence, нужно is part of an impersonal construction:

• нужно + infinitive

So:

• нужно подтвердить = it is necessary to confirm / needs to be confirmed

A few similar words are:

• нужно = necessary, needed
• надо = need to, have to
• необходимо = necessary, often more formal

In everyday speech, нужно and надо are often very close in meaning.

Because after нужно, Russian commonly uses the infinitive.

The pattern is:

• нужно + infinitive

Examples:

• Нужно подождать. = It is necessary to wait.
• Нужно проверить документ. = The document needs to be checked.
• Нужно подтвердить перевод. = The translation needs to be confirmed.

So подтвердить stays in its dictionary form because it is not being conjugated for a person like я, ты, or они.

This is a question of aspect.

• подтвердить = perfective
• подтверждать = imperfective

Russian uses the perfective here because the sentence is about achieving a result: the translation should end up confirmed.

So нужно подтвердить suggests:

• the action should be completed
• there should be a finished outcome

If you used подтверждать, it would sound more like an ongoing, repeated, or general process, which does not fit as well here.

It can correspond to both, depending on context.

Russian often leaves the doer of the action unstated in this kind of sentence.

So Этот перевод нужно подтвердить can mean:

• This translation needs to be confirmed
  focus on the translation itself

or

• We need to confirm this translation
  focus on what someone has to do

English usually forces you to choose one wording, but Russian does not always need to.

Russian word order is flexible, and the beginning of the sentence often shows what the sentence is about.

Putting этот перевод first makes it the topic:

• Этот перевод нужно подтвердить.
  = As for this translation, it needs to be confirmed.

A different order is also possible:

• Нужно подтвердить этот перевод.

This version is also correct, but it sounds a little more neutral or action-focused.

So the difference is mostly one of emphasis and information structure, not basic grammar.

Yes. That is perfectly natural.

• нужно and надо are both common here
• both mean something like need to or must

Very roughly:

• надо often sounds a bit more conversational
• нужно can sound slightly more neutral
• необходимо sounds more formal

So all of these are possible:

• Этот перевод нужно подтвердить.
• Этот перевод надо подтвердить.
• Этот перевод необходимо подтвердить.

It most directly means confirm, but in some contexts English might translate it as verify.

The core idea of подтвердить is:

• to establish that something is correct, valid, true, or approved

Depending on context, English could use:

• confirm
• verify
• approve
• validate

For example, with a translation, confirm is often the most straightforward choice, but the exact English wording depends on what kind of confirmation is meant.

It is generally neutral.

Nothing in Этот перевод нужно подтвердить is especially slangy or especially formal.

• этот = normal
• перевод = normal
• нужно = neutral
• подтвердить = neutral

So it would fit many everyday, workplace, or administrative contexts. If you wanted a more formal tone, you might say:

• Этот перевод необходимо подтвердить.

But the original sentence is completely standard and natural.