Problema este serioasă.

The basic dictionary form is problemă = problem.

In problema, the final -a is the definite article attached to the noun, so problema means the problem.

This is very common in Romanian: the definite article usually goes at the end of the noun instead of being a separate word like English the.

• problemă = a problem
• problema = the problem

So in this sentence, problema is not just problem; it is specifically the problem.

Because many Romanian feminine nouns ending in -ă change that ending when they become definite.

Here is the pattern:

• o problemă = a problem
• problema = the problem

So the indefinite ending -ă becomes -a when the definite article is added.

This is a normal pattern for many feminine singular nouns.

Este means is.

It is the 3rd person singular present tense form of the verb a fi = to be.

So:

• eu sunt = I am
• tu ești = you are
• el/ea este = he/she/it is

In your sentence, Problema este serioasă, este is simply the verb is.

Yes. Very often, especially in everyday speech, Romanian uses e instead of este.

So both are correct:

• Problema este serioasă.
• Problema e serioasă.

The version with este sounds a bit more careful or formal, while e is very common in normal conversation.

Because the adjective has to agree with the noun.

Problema is a feminine singular noun, so the adjective must also be feminine singular:

• masculine singular: serios
• feminine singular: serioasă

So:

• un lucru serios = a serious thing (masculine/neuter singular form)
• o problemă serioasă = a serious problem (feminine singular form)

Since problema is feminine singular, serioasă is the correct form.

You usually learn the noun together with an article or from its forms.

For example:

• o problemă = a problem

Because it uses o, that tells you it is feminine singular.

Also, the adjective agreement confirms it:

• problemă serioasă

Both the noun pattern and the adjective form show that the noun is feminine.

In this sentence, serioasă is a predicate adjective, not an adjective directly attached inside the noun phrase.

Structure:

• Problema = subject
• este = linking verb (is)
• serioasă = adjective describing the subject

This is exactly like English The problem is serious.

If you wanted the adjective directly next to the noun, you would say:

• problema serioasă = the serious problem

So compare:

• Problema este serioasă. = The problem is serious.
• problema serioasă = the serious problem

The normal, neutral order is:

• Problema este serioasă.

Romanian does allow some flexibility, but changing the order usually changes the emphasis or makes the sentence sound literary or marked.

For example, you might see:

• Serioasă este problema.

This is not the most neutral everyday order. It sounds more emphatic, like Serious is the problem / The problem is what’s serious.

So for a learner, the best standard version is:

• Problema este serioasă.

No. Romanian usually does not require a subject pronoun when the subject is already expressed.

Here the subject is problema, so adding ea would usually be unnecessary:

• Problema este serioasă. = normal
• Ea este serioasă. = It/She is serious, but only if the subject is already known from context

Romanian often leaves out pronouns unless they are needed for contrast or emphasis.

A helpful approximation is:

pro-BLE-ma ES-te se-ri-OA-să

A few pronunciation notes:

• ă is a short neutral vowel, like the a in English sofa
• oa in serioasă is a diphthong, pronounced together
• the stress is roughly:
  • proBLEma
  • ESte
  • seriOAsă

So the final word is not se-ri-o-a-să as four separate strong vowels; oa is grouped together.

ă is a very common Romanian vowel. It sounds like a short, relaxed uh sound, similar to the unstressed vowel in English about or sofa.

Examples from this sentence:

• problemă
• serioasă

In serioasă, the final -să ends with that ă sound.

It is different from plain a, which is a clearer open a sound.

This exact form, serioasă, is the feminine singular form.

The adjective changes depending on gender and number. For example:

• serios = masculine singular
• serioasă = feminine singular
• serioși = masculine plural
• serioase = feminine plural

So serioasă is not the only form of the adjective; it is the one that matches problema.

If you want to say A problem is serious, the straightforward form would be:

• O problemă este serioasă.

But in real usage, that sentence may sound a bit odd by itself unless the context makes it clear why you mean a problem rather than the problem.

Most often, the natural contrast is simply:

• o problemă = a problem
• problema = the problem

So the sentence you were given is specifically about the problem.

Because Romanian usually expresses definiteness by attaching the article to the end of the noun.

English:

• the problem

Romanian:

• problema

This is one of the major differences between Romanian and English grammar.

So instead of a separate article before the noun, Romanian often uses an ending on the noun itself.

Normally, no. In standard Romanian, problema is clearly the problem.

If you want just problem in the indefinite sense, you use:

• problemă in dictionary form
• usually o problemă in an actual sentence

So in this sentence, problema should definitely be understood as the problem.

It is perfectly normal Romanian and can be used in both formal and everyday contexts.

The only slightly more formal feature is este instead of e.

So:

• Problema este serioasă. = standard, a bit more careful
• Problema e serioasă. = very common in everyday speech

Both are natural.

Usually it matches English serious very well, especially in a sentence like this.

So Problema este serioasă means that the problem is important, grave, not minor, and should be taken seriously.

As in English, the exact nuance depends on context, but here it is a very direct equivalent of serious.

It is:

subject + verb + adjective

More exactly:

• Problema = subject noun phrase (the problem)
• este = linking verb (is)
• serioasă = predicate adjective (serious)

So the sentence is a very typical copular structure, just like English:

• The problem is serious.

This makes it a useful beginner sentence because it shows:

• the Romanian definite article
• the verb a fi
• adjective agreement with a feminine noun