Ma leúszom két kilométert.

Le- is a verb prefix, and here it gives the idea of completing or covering the distance by swimming.

So:

• úszom = I am swimming / I swim
• leúszom = I swim it off / I complete it by swimming

In this sentence, leúszom két kilométert suggests I will swim the full two kilometers, not just that I will be in the water swimming in general.

With distance expressions, prefixes like this often make the action sound more bounded or goal-oriented.

Hungarian often uses the present tense for a planned or expected future action, especially when there is a time word making the time clear.

Here, ma already tells you the action happens today, so leúszom can naturally mean:

• I’m swimming two kilometers today
• I’ll swim two kilometers today

This is very common in Hungarian. If you wanted a more explicitly future wording, Hungarian can also use fog:

• Ma le fogok úszni két kilométert.

But the original sentence sounds very natural and often a bit more direct or definite.

Because in a neutral statement, a Hungarian verb prefix normally stays attached to the verb.

So:

• le + úszom → leúszom

However, the prefix can separate from the verb in certain sentence patterns, especially with:

• negation
• focus
• some kinds of emphasis

For example:

• Nem úszom le a két kilométert. = I won’t swim the two kilometers.
• Két kilométert úszom le ma. = It’s two kilometers that I’m swimming today.

So in your sentence, it is one word because the sentence is structurally neutral.

The ending -om marks first person singular, so the verb means I swim / I will swim.

The structure is roughly:

• le- = verbal prefix
• úsz- = verb stem related to swim
• -om = I

So leúszom means I complete/swim it.

A learner may notice that Hungarian verb endings can be complicated, and this is true. But for this sentence, the key point is simple:

• leúszom = I swim it / I will swim it

The -t is the accusative ending, which often marks the direct object.

In Hungarian, a distance can be treated as the object of verbs like walk, run, or swim:

• két kilométert = two kilometers as the amount/distance covered

So Hungarian structures this as something like:

• I swim two kilometers

where two kilometers is grammatically the object, so it gets -t.

That is why you see:

• kilométer → kilométert

In Hungarian, két is normally used directly before a noun, while kettő is usually used when the number stands more independently.

So:

• két kilométer = two kilometers
• kettő = two, when standing alone or when emphasized

Examples:

• Két kilométert úszom. = I’m swimming two kilometers.
• Hány kilométert úszol? – Kettőt. = How many kilometers are you swimming? – Two.

So in your sentence, két is the normal choice because it comes right before kilométert.

Putting ma first is a very natural way to set the time frame: as for today / today.

Hungarian word order is flexible, and the beginning of the sentence often shows what the speaker wants to present as the starting point or topic.

So:

• Ma leúszom két kilométert.

sounds like:

• Today, I’m swimming two kilometers.

It is not the only possible word order, but it is a very natural one.

Yes. Hungarian word order is flexible, but different orders can change the focus or emphasis.

For example:

• Ma leúszom két kilométert.
  Neutral: Today I’ll swim two kilometers.

• Két kilométert úszom le ma.
  Focus on the distance: It’s two kilometers that I’m swimming today.

Notice something important: when a different element is strongly focused before the verb, the prefix often moves away from the verb:

• neutral: leúszom
• focused object: két kilométert úszom le

So word order is not random; it interacts with meaning and emphasis.

Yes, it is possible, but it is not exactly the same in feel.

• Ma úszom két kilométert.
  This can simply mean Today I’m swimming two kilometers.

• Ma leúszom két kilométert.
  This more strongly suggests Today I’ll get through / complete two kilometers.

So the version with le- sounds a bit more like a completed target or achievement, while the version without the prefix can be more neutral.

Most naturally, it sounds like a plan or intention for today.

Because of ma and the present-tense verb, a listener will usually understand something like:

• I’m doing two kilometers today
• I’ll swim two kilometers today

It does not usually sound like the person is literally in the middle of swimming at the moment they say it. It sounds more like a statement of intention or schedule.