Σήμερα νυστάζω πολύ, γιατί δεν κοιμήθηκα καλά και έχω πολλή νύστα από το πρωί.

Yes, they are very close in meaning.

• νυστάζω is a verb and means I feel sleepy / I’m getting sleepy.
• έχω νύστα literally means I have sleepiness, but in natural English it also means I’m sleepy.

In this sentence, both are used together for emphasis and variety:

• Σήμερα νυστάζω πολύ = Today I feel very sleepy
• έχω πολλή νύστα = I’m very sleepy / I have a lot of sleepiness

Greek often allows this kind of repetition when it sounds natural and expressive.

It is somewhat repetitive, but naturally so. Greek often uses two similar expressions in the same sentence to reinforce an idea.

Here, the speaker is strongly emphasizing their tiredness:

• νυστάζω πολύ states the condition
• έχω πολλή νύστα από το πρωί adds that this feeling has been going on since the morning

So the repetition is not awkward. It sounds like natural spoken emphasis.

Because the two words are doing different jobs.

• πολύ is an adverb here, modifying the verb νυστάζω. It means a lot / very much.

  • νυστάζω πολύ = I’m very sleepy

• πολλή is an adjective here, agreeing with the noun νύστα, which is feminine singular.

  • πολλή νύστα = a lot of sleepiness

So:

• πολύ = adverb
• πολλή = feminine singular adjective

This is a very common Greek pattern:

• δουλεύω πολύ = I work a lot
• έχω πολλή δουλειά = I have a lot of work

κοιμήθηκα is the aorist form, which usually expresses a completed past action.

So:

• δεν κοιμήθηκα καλά = I didn’t sleep well

In English, we often just use the simple past didn’t sleep well, and that matches nicely here.

The aorist is used because the speaker is referring to last night’s sleep as a completed event.

This is normal for Greek. The dictionary form is κοιμάμαι = I sleep / I am sleeping, but many Greek verbs have a different-looking aorist stem.

Here are the key forms:

• κοιμάμαι = I sleep / I am sleeping
• κοιμήθηκα = I slept

This is a very common type of verb pattern in Modern Greek. It may feel strange at first because the present and past forms are not built in the same way English learners expect.

You do not need to translate it literally as something like I got slept or anything similar. Just learn it as the normal past form of κοιμάμαι.

Because καλά is the adverb form here, meaning well.

• καλός, καλή, καλό are adjective forms meaning good
• καλά can function as an adverb meaning well

So:

• δεν κοιμήθηκα καλά = I didn’t sleep well

Compare:

• καλό βιβλίο = good book
• μιλάει καλά = he/she speaks well

από το πρωί literally means from the morning, but in natural English it usually means:

• since the morning
• since this morning
• all morning, depending on context

In this sentence:

• έχω πολλή νύστα από το πρωί = I’ve been very sleepy since this morning

It expresses a starting point in time that continues up to now.

Because Greek usually does not need subject pronouns. The verb ending already shows the subject.

For example:

• νυστάζω = I am sleepy / I feel sleepy
• κοιμήθηκα = I slept
• έχω = I have

So εγώ is normally omitted unless the speaker wants emphasis or contrast.

For example:

• Εγώ νυστάζω, αλλά αυτός όχι. = I’m sleepy, but he isn’t.

In your sentence, no extra emphasis is needed, so the pronoun is left out.

Yes. γιατί can mean both:

• why
• because

The meaning depends on the sentence.

In your example:

• γιατί δεν κοιμήθηκα καλά = because I didn’t sleep well

Compare:

• Γιατί νυστάζεις; = Why are you sleepy?
• Νυστάζω γιατί δεν κοιμήθηκα καλά. = I’m sleepy because I didn’t sleep well.

This is very common in Greek and usually causes no confusion in context.

The word order is fairly natural, but not completely fixed. Greek is more flexible than English because the verb endings and case system help show relationships.

The original sentence:

• Σήμερα νυστάζω πολύ, γιατί δεν κοιμήθηκα καλά και έχω πολλή νύστα από το πρωί.

This order sounds natural and neutral. But other orders are possible for emphasis, for example:

• Νυστάζω πολύ σήμερα...
• Από το πρωί έχω πολλή νύστα...

Changing the order often changes emphasis rather than core meaning.

No. σήμερα can appear in different places.

For example:

• Σήμερα νυστάζω πολύ.
• Νυστάζω πολύ σήμερα.

Both are correct. Putting σήμερα first often gives it slightly more prominence, as if setting the scene: As for today...

So in your sentence, starting with Σήμερα is very natural.

Yes, there is a difference in nuance.

• δεν κοιμήθηκα καλά = I didn’t sleep well

  • simple completed past event
  • most natural here when talking about last night

• δεν έχω κοιμηθεί καλά = I haven’t slept well

  • present perfect idea
  • can suggest a period leading up to now, not just one night

In this sentence, δεν κοιμήθηκα καλά fits best because the speaker is most likely referring to one specific sleep period, probably last night.

Yes, very common. νύστα is an everyday word meaning sleepiness / drowsiness.

You will often hear:

• Έχω νύστα. = I’m sleepy.
• Μου έρχεται νύστα. = I’m getting sleepy.
• Με πιάνει νύστα. = I get sleepy / sleepiness comes over me.

So this sentence uses very natural, common vocabulary.