La nivelul acesta, pot să înțeleg fiecare expresie.

Both are correct, and both mean at this level.

The difference is mostly one of structure and style:

• la acest nivel = demonstrative before the noun
• la nivelul acesta = noun with the definite article, then the demonstrative after it

Romanian often allows both patterns:

• acest nivel
• nivelul acesta

The version in your sentence, la nivelul acesta, can sound a bit more pointed or conversational, while la acest nivel is also very common and may feel slightly more neutral or compact.

So:

• La nivelul acesta, pot să înțeleg...
• La acest nivel, pot să înțeleg...

Both are natural.

Because Romanian uses the definite article attached to the end of the noun.

So:

• nivel = level
• nivelul = the level

In nivelul acesta, the idea is literally this level, and Romanian commonly expresses that with:

• definite noun + demonstrative

So:

• nivelul acesta = this level

This is different from English, where the is a separate word.

Acesta means this.

In this sentence, it matches nivelul, which is:

• masculine
• singular

So acesta is the masculine singular form of this.

A few related forms are:

• acesta = this (masculine singular)
• aceasta = this (feminine singular)
• acești = these (masculine plural)
• aceste = these (feminine/neuter plural)

Since nivel is masculine singular, acesta is the correct form.

In Romanian, demonstratives can appear either before or after the noun, but the structure changes slightly.

Compare:

• acest nivel
• nivelul acesta

When the demonstrative comes after the noun, the noun is typically definite:

• nivelul acesta

When it comes before the noun, you usually get:

• acest nivel

Both mean this level.

This postposed pattern is very common in Romanian and may feel unusual to English speakers at first, because English normally puts this before the noun.

Because Romanian usually uses a putea (to be able / can) with a verb in the subjunctive:

• pot să înțeleg = I can understand

This is one of the most common Romanian patterns:

• pot să merg = I can go
• pot să citesc = I can read
• pot să vorbesc = I can speak

For an English speaker, it may feel strange because English uses can + bare verb:

• I can understand

But in Romanian, pot să înțeleg is the normal modern pattern.

Yes, you may encounter pot înțelege, and it is understandable Romanian. However, pot să înțeleg is generally the more common and everyday form.

So for learners, the safest choice is:

• pot să înțeleg

You should definitely recognize pot înțelege if you see it, but if you are producing the language yourself, pot să înțeleg is usually the best default.

Because after să, Romanian uses a conjugated verb, not the infinitive.

So:

• a înțelege = to understand (infinitive)
• înțeleg = I understand (1st person singular present)
• să înțeleg = that I understand / to understand, in the subjunctive pattern

In pot să înțeleg:

• pot = I can
• să înțeleg = understand

Even though English thinks of this as can understand, Romanian grammar treats it as a să + finite verb construction.

Fiecare means each or every, and it is followed by a singular noun in Romanian.

So:

• fiecare expresie = each expression / every expression

This is very normal in Romanian:

• fiecare zi = every day
• fiecare cuvânt = every word
• fiecare expresie = every expression

Even though the meaning is collective in English, Romanian still uses the singular noun after fiecare.

They are similar, but not identical.

• fiecare expresie = each / every expression
• toate expresiile = all the expressions

Fiecare emphasizes items one by one, individually. Toate expresiile refers to the whole set as a group.

So:

• Pot să înțeleg fiecare expresie = I can understand every expression
• Pot să înțeleg toate expresiile = I can understand all the expressions

In many contexts, both could work, but fiecare has a more distributive sense.

It can depend on context.

Expresie often does mean expression, but in language-learning contexts it can sometimes overlap with phrase or idiomatic expression, depending on what the speaker has in mind.

So in this sentence, fiecare expresie could mean:

• every expression
• every phrase
• every expression I come across

If someone wanted to be more specifically phrase, they might use frază in some contexts, but expresie is perfectly natural if the idea is about language chunks or expressions.

The comma separates the introductory phrase from the main clause:

• La nivelul acesta, = At this level,
• pot să înțeleg fiecare expresie. = I can understand every expression.

This kind of comma is common when a sentence begins with a contextual phrase such as time, place, condition, or point of view.

It helps readability, though in some short sentences Romanian punctuation can be somewhat flexible. Here, the comma is perfectly natural.

Yes, absolutely.

La nivelul acesta is a natural Romanian way to talk about someone’s level, stage, or degree of ability.

For example:

• La nivelul acesta, citesc fără probleme. = At this level, I read without problems.
• La nivelul acesta, pot purta o conversație simplă. = At this level, I can hold a simple conversation.

So the phrase sounds normal and idiomatic.

Yes. That would also be correct, but the meaning changes slightly.

• pot să înțeleg fiecare expresie = I can understand every expression
• înțeleg fiecare expresie = I understand every expression

The version with pot să emphasizes ability. The version without it sounds more direct and factual.

So if the point is about capability at a certain proficiency level, pot să înțeleg is a very good choice.