Τα παιδιά κολυμπούν στην πισίνα.

Because παιδιά is a neuter plural noun.

In Greek, the definite article has to match the noun’s gender, number, and case:

• ο / η / το = singular
• οι / τα = plural

More specifically:

• οι is used for masculine and feminine plural nouns
• τα is used for neuter plural nouns

Since παιδιά is the plural of παιδί and is neuter, the correct article is τα.

So:

• το παιδί = the child
• τα παιδιά = the children

The singular is παιδί.

So the pair is:

• το παιδί = the child
• τα παιδιά = the children

This is a very common noun, and it is useful to memorize it as a full pair because the plural is not formed in a way that looks exactly like English.

Because the subject is plural: τα παιδιά = the children.

Κολυμπούν is the 3rd person plural present form of the verb κολυμπώ / κολυμπώ (to swim).

So the logic is:

• το παιδί κολυμπά = the child swims / is swimming
• τα παιδιά κολυμπούν = the children swim / are swimming

Even though παιδιά is neuter, the important thing for the verb ending here is that it is plural.

Not in the same way it does for articles and adjectives.

The verb κολυμπούν agrees with the subject in person and number, not in gender.

So:

• το παιδί κολυμπά → singular
• τα παιδιά κολυμπούν → plural

The fact that παιδιά is neuter affects the article τα, but not the verb ending itself.

Because Greek often drops subject pronouns when they are not needed.

English usually says:

• They are swimming

Greek often just uses the verb, because the ending already gives person and number, or because the subject noun is explicitly stated:

• Τα παιδιά κολυμπούν

Adding αυτά or another pronoun would usually be unnecessary here unless you want extra emphasis or contrast.

Στην is a contraction of:

• σε
  • την → στην

Here:

• σε = in / to / at / on, depending on context
• την = the (feminine singular, accusative)

So:

• στην πισίνα literally corresponds to in the pool

This contraction is extremely common in everyday Greek.

You will also see similar forms such as:

• στο = σε + το
• στον = σε + τον
• στις = σε + τις
• στα = σε + τα

Because σε normally takes the accusative in Modern Greek.

So after σε, the noun phrase usually appears in the accusative form:

• στην πισίνα
• στο σπίτι
• στον δρόμο

In this sentence, πισίνα is feminine singular, and its accusative singular article is την, which becomes στην after σε.

A useful thing to remember is that Modern Greek often uses σε + accusative where older Greek or some other languages might use a distinct locative or dative idea.

It can mean any of those depending on context.

Σε is very flexible. It can correspond to English:

• in
• at
• to
• sometimes on

In this sentence, στην πισίνα is naturally understood as in the pool, because the action is swimming.

Examples:

• Πάω στην πισίνα. = I’m going to the pool.
• Είμαι στην πισίνα. = I’m at/in the pool.
• Τα παιδιά κολυμπούν στην πισίνα. = The children are swimming in the pool.

It can cover both.

The Greek present tense often corresponds to either:

• swim
• are swimming

The exact English translation depends on context.

So:

• Τα παιδιά κολυμπούν στην πισίνα. could mean
  • The children swim in the pool
  • The children are swimming in the pool

In many contexts, English prefers are swimming, but Greek itself does not need a separate form here.

Yes. Greek word order is more flexible than English.

The neutral, straightforward order here is:

• Τα παιδιά κολυμπούν στην πισίνα.

But other orders are possible, for example:

• Στην πισίνα κολυμπούν τα παιδιά.
• Κολυμπούν τα παιδιά στην πισίνα.

These versions may shift the focus or emphasis, but the basic meaning stays the same.

English is much stricter about word order, while Greek often uses word order more for emphasis and information structure.

A simple learner-friendly pronunciation is:

• ko-lee-boon

A few helpful notes:

• υ here sounds like ee
• μπ inside a word is usually pronounced like b
• the final -ούν is stressed, so the stress falls on the last syllable

So κολυμπούν sounds roughly like ko-lee-BOON.

A rough pronunciation guide is:

• Ta peh-THYA ko-lee-BOON steen pee-SEE-na

A few key points:

• παιδιά sounds roughly like peh-THYA
• στην sounds like steen
• πισίνα sounds like pee-SEE-na
• stress matters in Greek, so pay attention to:
  • παιδιά
  • κολυμπούν
  • πισίνα

Greek often uses the definite article more naturally than English does, especially with general or identifiable nouns.

So Τα παιδιά κολυμπούν στην πισίνα is perfectly normal Greek.

Depending on context, English might say:

• The children are swimming in the pool
• Children are swimming in the pool

But in Greek, using τα παιδιά is very natural when referring to a known group or a specific set of children in the situation.

It is a common Modern Greek word and is widely used in everyday speech, but it is a loanword.

For learners, the important thing is that πισίνα is the normal everyday word for pool / swimming pool.

It is a feminine noun, so:

• η πισίνα = the pool
• την πισίνα = the pool (accusative)
• στην πισίνα = in/to the pool

Yes, it could.

The Greek present tense can describe:

• something happening right now
• something happening habitually
• something generally true

So without extra context, Τα παιδιά κολυμπούν στην πισίνα may mean either:

• The children are swimming in the pool
  or
• The children swim in the pool

Context tells you which meaning is intended.