Falta um acento nesta palavra, e a vírgula também está no lugar errado.

In Portuguese, faltar often means to be missing rather than to lack in the English structure.

So Falta um acento nesta palavra literally works like:

• An accent mark is missing in this word

The important idea is that the thing missing becomes the grammatical subject in Portuguese.

• Falta um acento. = One accent mark is missing.
• Faltam dois acentos. = Two accent marks are missing.

This is a very common pattern in Portuguese.

Because the subject is um acento, which is singular.

Portuguese verbs agree with the subject:

• Falta um acento. = singular
• Faltam dois acentos. = plural

Even though English might focus on there is/there are, Portuguese is really matching the verb to the missing thing.

Here, acento means an accent mark or diacritic in writing, not a spoken accent.

So in this sentence, um acento means something like:

• á, ê, ç-type written marks

Portuguese acento can also mean accent in the sense of pronunciation or regional speech, but the context makes it clear that this sentence is talking about spelling and punctuation.

Nesta is a contraction of:

• em + esta = nesta

Portuguese commonly combines prepositions with articles and demonstratives.

So:

• nesta palavra = in this word

You normally would not say em esta palavra in standard Portuguese.

Because palavra is a feminine noun.

The demonstrative has to agree with the noun:

• este / neste for masculine singular nouns
• esta / nesta for feminine singular nouns

So:

• neste livro = in this book
• nesta palavra = in this word

Yes, especially in everyday Brazilian Portuguese, nessa palavra is very common.

Traditional grammar usually makes a distinction like this:

• nesta = in this, closer to the speaker or the current text
• nessa = in that, closer to the listener or something already mentioned

But in modern Brazilian usage, that distinction is often weaker in speech, and nessa frequently replaces nesta.

So:

• nesta palavra sounds correct and a bit more formal or careful
• nessa palavra is also very natural in Brazil

Também means also or too.

In this sentence:

• a vírgula também está no lugar errado

it means that, besides the missing accent mark, the comma is also wrong.

Its position is very natural in Portuguese. Adverbs like também are somewhat flexible, but this placement is common and clear.

Compare:

• A vírgula também está no lugar errado. = The comma is also in the wrong place.
• Também falta um acento. = An accent is also missing.

Because Portuguese normally uses estar for location or position.

• estar = to be, in a place/state/position
• ser = to be, in the sense of identity or essential characteristic

So:

• A vírgula está no lugar errado. = The comma is in the wrong place.

That is about where the comma is positioned, so estar is the natural verb.

No is a contraction of:

• em + o = no

So:

• no lugar errado = in the wrong place

This kind of contraction is extremely common in Portuguese:

• na = em + a
• nos = em + os
• nas = em + as

Because errado is agreeing with lugar, not with vírgula.

The phrase is:

• no lugar errado = in the wrong place

Here, errado describes lugar:

• lugar is masculine
• so the adjective is errado

If you were describing the comma itself directly, then you would say:

• a vírgula errada = the wrong comma

But that is not the structure here.

Because vírgula is stressed on the first syllable:

• VÍR-gu-la

Words stressed on the antepenultimate syllable are called proparoxytones, and in Portuguese they always take a written accent.

So vírgula must be written with the accent.

It can appear, but many speakers would leave it out.

A very common version would be:

• Falta um acento nesta palavra e a vírgula também está no lugar errado.

In Portuguese, you usually do not put a comma before e when it simply joins two coordinated parts of a sentence. However, some writers do use it:

• when the clauses are longer
• when the subjects are different
• for rhythm or emphasis

So the comma is not shocking, but omitting it would often sound more standard and smoother.

A fairly literal translation would be:

• An accent mark is missing in this word, and the comma is also in the wrong place.

Word by word, it is roughly:

• Falta = is missing
• um acento = an accent mark
• nesta palavra = in this word
• e = and
• a vírgula = the comma
• também = also
• está = is
• no lugar errado = in the wrong place

That literal view helps show how Portuguese is structuring the idea.