Ποιο είναι το πρόβλημα;

A natural pronunciation is roughly:

POH-yo EE-ne to PROV-lee-ma?

A more careful breakdown:

• Ποιο = POH-yo
• είναι = EE-ne
• το = to
• πρόβλημα = PROV-lee-ma

A few notes:

• οι in Ποιο sounds like ee in Modern Greek, but because of the surrounding vowels, the word sounds like two syllables: POH-yo.
• β in Modern Greek is pronounced like v, not like English b.
• The stress falls on:
  • ΠΟΙο
  • ΕΙναι
  • ΠΡΟβλημα

Ποιο here means which or what, depending on the English translation.

In this sentence, Ποιο είναι το πρόβλημα; is most naturally translated as What is the problem?

Greek often uses ποιος / ποια / ποιο where English might simply use what. Literally, the structure is closer to Which is the problem?, but in natural English that becomes What is the problem?

By contrast, Τι είναι το πρόβλημα; is not the normal way to ask this.

Because πρόβλημα is a neuter noun in Greek.

The question word ποιος changes to match the gender of the noun:

• ποιος = masculine
• ποια = feminine
• ποιο = neuter

Since το πρόβλημα is neuter, the correct form is ποιο.

In Greek, the definite article is used very regularly, and here το πρόβλημα means the problem.

So:

• το = the for a neuter singular noun
• πρόβλημα = problem

Together: το πρόβλημα = the problem

In this sentence, the article is completely normal and expected.

είναι means is.

It is the 3rd person singular form of the verb είμαι = to be.

So:

• είμαι = I am
• είναι = he/she/it is

In this sentence:

• Ποιο = what/which
• είναι = is
• το πρόβλημα = the problem

So the structure is literally Which/what is the problem?

Greek word order is more flexible than English, but Ποιο είναι το πρόβλημα; is the most natural and standard order here.

You may also hear:

• Ποιο το πρόβλημα;

This is shorter and more colloquial, almost like What’s the problem?

But for learners, Ποιο είναι το πρόβλημα; is the safest full version to use.

It depends a lot on tone of voice and context.

It can be:

• completely neutral: What is the problem?
• concerned/helpful: What seems to be the problem?
• confrontational: What’s your problem?

So the Greek sentence itself is not automatically rude, but if said sharply, it can sound aggressive. This is very similar to English.

Yes, in the right context it can.

Literally, Ποιο είναι το πρόβλημα; means What is the problem?, but depending on tone and situation, it may be understood like:

• What’s the problem?
• What’s your problem?

If someone says it in an annoyed way, it can sound challenging.

If you want a clearly polite version, you could say something like:

• Ποιο είναι το πρόβλημα; Μπορώ να βοηθήσω;
  = What is the problem? Can I help?

Yes. πρόβλημα is one of many Greek nouns ending in -μα, and these are usually neuter.

Examples:

• το πρόβλημα = the problem
• το γράμμα = the letter
• το όνομα = the name
• το μάθημα = the lesson

So the ending -μα is a helpful clue that the noun is probably neuter.

It is in the nominative neuter singular.

That is because it matches το πρόβλημα, which is also nominative neuter singular in this sentence.

The sentence is an equational sentence with to be:

• Ποιο = what/which
• είναι = is
• το πρόβλημα = the problem

Since ποιο refers to the thing being identified, nominative is used.

A few simple answers are:

• Το πρόβλημα είναι ο θόρυβος.
  = The problem is the noise.

• Δεν υπάρχει πρόβλημα.
  = There is no problem.

• Το πρόβλημα είναι ότι αργήσαμε.
  = The problem is that we were late.

• Αυτό είναι το πρόβλημα.
  = That is the problem.

These are good patterns to learn because they reuse το πρόβλημα and είναι.

Yes, depending on the situation.

Some common alternatives are:

• Ποιο είναι το πρόβλημα;
  Standard and complete.

• Ποιο το πρόβλημα;
  Shorter, more conversational.

• Τι πρόβλημα υπάρχει;
  Literally What problem is there? / What seems to be the problem?
  This can sound a bit more formal or practical, depending on context.

For a learner, Ποιο είναι το πρόβλημα; is the clearest version to start with.