Μην τσαλακώνεις το πουκάμισο στην τσάντα, γιατί θα χρειαστεί πάλι σιδέρωμα.

Because Μην is used for negative commands in Modern Greek.

• Μην τσαλακώνεις... = Don’t wrinkle/crumple...
• Δεν τσαλακώνεις... would mean something like You are not wrinkling..., which is just a statement, not a command.

So Μην is the normal word you use when telling someone not to do something.

That is very normal in Greek. Negative commands are not formed with a special negative imperative form. Instead, Greek uses:

μην + subjunctive form

With many verbs, the imperfective subjunctive looks the same as the present-tense form. So:

• τσαλακώνεις can look like you wrinkle / you are wrinkling
• but after μην, it means don’t wrinkle / don’t be wrinkling

So Μην τσαλακώνεις is a perfectly standard way to say Don’t wrinkle it.

This is an aspect difference, which is very important in Greek.

• Μην τσαλακώνεις = negative command with imperfective aspect
  This often sounds like don’t keep wrinkling it, don’t wrinkle it in general, or don’t handle it in a way that wrinkles it.

• Μην τσαλακώσεις = negative command with perfective aspect
  This often sounds more like don’t wrinkle it even once or don’t let it get wrinkled as a single event.

In everyday speech, both can be possible depending on what nuance the speaker wants. In this sentence, Μην τσαλακώνεις suggests avoiding the action/process.

Τσαλακώνω means to wrinkle, crease, crumple, or make something rumpled.

It is often used for:

• clothes
• paper
• fabric

So with το πουκάμισο, it means to make the shirt wrinkled/creased.

Πουκάμισο is a neuter noun, so its article is το.

Here, το πουκάμισο is the direct object of the verb τσαλακώνεις.

A useful detail: with many neuter nouns in Greek, the nominative and accusative forms are the same, so το πουκάμισο looks the same whether it is the subject or the object.

Στην is a contraction of:

σε + την = στην

So στην τσάντα means in the bag or sometimes into the bag, depending on context.

Greek σε is very flexible and can cover meanings that English splits into:

• in
• into
• at
• to
• sometimes on

Here the natural idea is in the bag or when putting it in the bag.

It can mean both, depending on context.

In this sentence, γιατί means because:

• ..., γιατί θα χρειαστεί πάλι σιδέρωμα.
• ..., because it will need ironing again.

When it introduces a question, it means why:

• Γιατί άργησες; = Why were you late?

So context tells you which meaning is intended.

Θα χρειαστεί means will need.

It comes from the verb χρειάζομαι, which means to need.

Here is the basic idea:

• χρειάζεται = it needs
• θα χρειαστεί = it will need

The form after θα is the perfective non-past form, which is commonly used to make the future in Greek when the action is seen as a single whole event.

So here, θα χρειαστεί means that later on, as a result, the shirt will need ironing.

The subject is understood from context: το πουκάμισο.

Greek often leaves out subjects when they are already clear. So the sentence does not need to repeat the noun.

The idea is:

• Μην τσαλακώνεις το πουκάμισο...
• because it will need ironing again

That it is the shirt.

Because σιδέρωμα here is being used as a general action noun, meaning ironing.

So:

• θα χρειαστεί πάλι σιδέρωμα = it will need ironing again

This is similar to English, where we also usually say need ironing, not need the ironing.

If you added the article, το σιδέρωμα, it would sound more like the ironing as a specific task or piece of work.

Σιδέρωμα is a noun meaning ironing.

It comes from the verb σιδερώνω, which means to iron.

So Greek is using a noun where English also often uses a noun-like gerund:

• needs ironing
• χρειάζεται σιδέρωμα

This is a very common Greek pattern.

Πάλι means again.

Here it modifies the idea of needing ironing again, and Greek often places adverbs like this before the noun or phrase they relate to:

• θα χρειαστεί πάλι σιδέρωμα

That sounds natural and idiomatic.

You may also hear ξανά in similar contexts:

• θα χρειαστεί ξανά σιδέρωμα

Both mean again, though πάλι is the word used in your sentence.

A helpful pronunciation guide is:

Min tsalakónis to poukámiso stin tsánda, yatí tha hriastí páli sideróma.

A few useful notes:

• τσ sounds like ts in cats
• χρ in χρειαστεί is harder for English speakers; χ is a throat sound, not an English h
• stress matters in Greek, so pay attention to:
  • τσαλακώνεις
  • πουκάμισο
  • τσάντα
  • χρειαστεί
  • σιδέρωμα

If you keep the stress in the right place, you will already sound much more natural.