La profesora dice que falta el punto final en esa frase.

La profesora means the teacher.

In Spanish, you often use the definite article (el, la, los, las) when you are talking about a specific person already identified in the context.

• La profesora = the teacher
• Una profesora = a teacher
• Profesora by itself is possible in some contexts, but not as the normal subject here.

So in this sentence, la profesora is simply the natural way to say the teacher.

Dice que means says that.

Here, que introduces reported speech or an indirect statement:

• La profesora dice que... = The teacher says that...

This is very common in Spanish:

• Dice que viene mañana. = He/She says that he/she is coming tomorrow.
• Mi amigo dice que está cansado. = My friend says that he is tired.

In English, that is often optional, but in Spanish que is normally required in this structure.

Because the grammatical subject is el punto final, which is singular.

Spanish faltar works a bit differently from English to be missing. The thing that is missing is the subject:

• Falta el punto final. = The full stop is missing.
• Faltan dos palabras. = Two words are missing.

So:

• el punto final → singular → falta
• dos puntos finales → plural → faltan

In this sentence, faltar means to be missing or to be lacking.

A useful way to think about it is:

• Falta X = X is missing
• Faltan X = X are missing

Examples:

• Falta una coma. = A comma is missing.
• Faltan tres páginas. = Three pages are missing.

This can feel backwards to an English speaker because Spanish makes the missing thing the subject.

In Spain, punto final is the usual term for the punctuation mark . at the end of a sentence.

• punto = point/dot/full stop/period, depending on context
• punto final = specifically the final full stop at the end of a sentence

So falta el punto final means the sentence is missing its ending punctuation mark.

In everyday classroom or grammar contexts in Spain, punto final sounds very natural.

Because en esa frase means in that sentence/phrase, which fits the idea of something being located inside it.

• falta el punto final en esa frase = the full stop is missing in that sentence

Using de would change the meaning and sound less natural here.

Compare:

• en esa frase = in that sentence
• al final de esa frase = at the end of that sentence

You could also say al final de esa frase if you want to be more explicit about the location of the missing punctuation.

Both are demonstratives, but they point to different degrees of distance:

• esta = this
• esa = that
• aquella = that over there / that one farther away

So:

• esta frase = this sentence
• esa frase = that sentence

In the given sentence, the speaker is referring to that sentence, not this sentence.

Spanish word order is more flexible than English word order.

The most neutral English structure is:

• The full stop is missing.

But in Spanish, it is very common to put the verb before the subject with verbs like faltar, especially when introducing what is missing:

• Falta el punto final.

This is completely natural. You could think of it as similar to:

• There is a full stop missing.

So the order is normal Spanish, not unusual or poetic.

Because dice que normally introduces a statement presented as fact, so Spanish uses the indicative:

• La profesora dice que falta el punto final.

The verb falta is therefore in the indicative, not the subjunctive.

You usually get the subjunctive after expressions of doubt, emotion, denial, influence, and so on, for example:

• Duda que falte el punto final. = She doubts that the full stop is missing.

But with dice que, the normal choice is the indicative.

Yes, that is possible, and it is a very natural alternative.

• Le falta el punto final a esa frase literally works like that sentence lacks the final full stop

Here, le refers to esa frase.

So you have two natural ways to express the idea:

• Falta el punto final en esa frase.
• A esa frase le falta el punto final.

Both are correct. The second one highlights the sentence as the thing that lacks something.

Not exactly.

• frase is a general word for phrase or sometimes sentence in non-technical use.
• oración is the more grammatical/technical term for a full sentence or clause.

In a classroom context, people may say either one depending on how precise they want to be.

So here, esa frase is perfectly normal, especially in everyday speech, even if a grammar book might sometimes prefer esa oración for that sentence.

Yes. Outside grammar, punto final can also mean an end, a final stop, or putting an end to something.

For example:

• Pusieron punto final a la discusión. = They put an end to the discussion.

But in your sentence, because of falta and en esa frase, the punctuation meaning is clearly the intended one.