Learn Hardcore Greek: Περπατάω γρήγορα στο πάρκο όταν δεν βρέχει. - I walk quickly in the park when it is not raining.

You can say Εγώ περπατάω γρήγορα… if you want to emphasize I (e.g. contrast: I walk fast, others don’t), but normally Greek just uses the verb form on its own.

What’s the difference between περπατάω and περπατώ? Are both correct?

Both are correct and mean “I walk”.

περπατάω – more common in everyday, spoken Greek.
περπατώ – a bit more formal/literary, but still used and correct.

Other forms (colloquial/common first; more formal second where it exists):

εγώ περπατάω / περπατώ – I walk
εσύ περπατάς – you walk
αυτός/αυτή/αυτό περπατάει / περπατά – he/she/it walks
εμείς περπατάμε / περπατούμε – we walk
εσείς περπατάτε – you (pl./formal) walk
αυτοί/αυτές/αυτά περπατάνε / περπατούν(ε) – they walk

So your sentence is using the standard everyday form.

Is γρήγορα an adjective or an adverb here? How would I say “I am fast” instead of “I walk fast”?

In Περπατάω γρήγορα, γρήγορα is an adverb: it describes how you walk (quickly).

Περπατάω γρήγορα. – I walk fast / quickly. (adverb)

The adjective is:

γρήγορος (masc.)
γρήγορη (fem.)
γρήγορο (neut.)

To say “I am fast” (describing you, not the manner of walking):

Είμαι γρήγορος – I am fast (if you’re male)
Είμαι γρήγορη – I am fast (if you’re female)

So:

Είμαι γρήγορος/γρήγορη. – I am fast.
Περπατάω γρήγορα. – I walk fast.

Can I move γρήγορα to another place in the sentence, like in English?

Yes, Greek word order is flexible, but default is:

Περπατάω γρήγορα στο πάρκο… – neutral, standard.

Other possibilities:

Περπατάω στο πάρκο γρήγορα όταν δεν βρέχει.
Still correct; the rhythm/emphasis shifts a bit, but meaning is the same.
Γρήγορα περπατάω στο πάρκο όταν δεν βρέχει.
Sounds more emphatic, like stressing quickly (It’s quickly that I walk in the park when it’s not raining).

Generally, keep verb + adverb close (like in the original sentence) for the most natural sound.

What exactly does στο mean? Is it one word or two?

στο is a contraction of:

σε (in, at, to) + το (the – neuter singular)

So:

σε + το πάρκο → στο πάρκο = in/at/to the park

Other common contractions:

σε + τον → στον (to the / in the – masculine)
- στον δρόμο – in the street
σε + τη(ν) → στη(ν) (to the / in the – feminine)
- στη δουλειά – at work

So στο πάρκο literally means “in the park” or “at the park”, depending on context, just like English uses in/at.

Why is it στο πάρκο and not just σε πάρκο? Does the article matter?

Yes, the article matters.

στο πάρκο = in the park (a specific, or “known” park to the speaker/listener).
σε πάρκο = in a park (some park, not specified — this is much less common in everyday speech unless you really mean “some random park”).

Greek tends to use the definite article more often than English, especially with places:

Πάω στο σχολείο. – I’m going to (the) school.
Πίνω καφέ στο σπίτι. – I drink coffee at (the) home.

So στο πάρκο is the most natural phrasing here.

What gender and case is πάρκο, and why does it end in -ο?

πάρκο is a neuter noun borrowed from a foreign word (like many neuter nouns in -ο).

In your sentence στο πάρκο, it is in the accusative singular, because:

The preposition σε (in/at/to) takes the accusative.
το πάρκο (nominative/accusative neuter singular) → στο πάρκο.

Basic forms:

το πάρκο – the park (nom./acc. singular)
του πάρκου – of the park (gen. singular)
τα πάρκα – the parks (nom./acc. plural)
των πάρκων – of the parks (gen. plural)

So the -ο ending is normal for many neuter nouns (το βιβλίο, το παιδί, το πάρκο, etc.).

Why is the negation δεν and not μην in όταν δεν βρέχει?

Greek has two main negative particles:

δεν – used with the indicative mood, i.e. normal statements of fact.
μη(ν) – used mainly with the subjunctive, imperatives, and some set expressions.

In your sentence:

βρέχει = it rains / it is raining → indicative present.
So you use δεν → δεν βρέχει = it doesn’t rain / it isn’t raining.

Examples:

Δεν βρέχει. – It is not raining.
Να μην βρέξει. – (I hope / let it) not rain.
Μην βγεις έξω. – Don’t go out.

Why doesn’t βρέχει have a subject? Where is the “it” from “it rains”?

Greek often uses impersonal verbs for weather, without a grammatical subject.

Βρέχει. – It is raining. (literally just “rains”)
Χιονίζει. – It’s snowing.
Αστράφτει. – There is lightning.

There is no word for “it” in these sentences. Greek simply uses 3rd person singular as an impersonal form.

So όταν δεν βρέχει = when it doesn’t rain / when it isn’t raining, but literally “when not-rains”.

What does όταν mean here, and how is it different from αν or πότε?

In όταν δεν βρέχει:

όταν = when / whenever (introducing a time clause).

Differences:

όταν – when (time):
- Όταν δεν βρέχει, περπατάω…
  When/whenever it doesn’t rain, I walk…
αν – if (condition):
- Αν δεν βρέχει, θα περπατήσω…
  If it doesn’t rain, I will walk…
πότε – when? (question word):
- Πότε περπατάς στο πάρκο; – When do you walk in the park?

So όταν ≈ when/whenever (non‑question), αν ≈ if, πότε ≈ when? (question).

Can I put όταν δεν βρέχει at the beginning of the sentence? Does the meaning change?

Yes, you can, and the meaning stays the same:

Περπατάω γρήγορα στο πάρκο όταν δεν βρέχει.
Όταν δεν βρέχει, περπατάω γρήγορα στο πάρκο.

Both mean: I walk fast in the park when it isn’t raining.

Differences:

Starting with Όταν δεν βρέχει slightly highlights the condition/time (As for when it isn’t raining… I walk fast in the park).
Starting with Περπατάω γρήγορα sounds more neutral, like English I walk fast in the park when it’s not raining.

Both orders are perfectly correct.

Does the Greek present περπατάω mean both “I walk” and “I am walking”, like in English?

Yes. Greek present tense often covers both the simple and continuous meanings:

Περπατάω γρήγορα στο πάρκο.
- I walk fast in the park (habitual)
- I am walking fast in the park (right now)

Context usually shows which one is meant. In your sentence, όταν δεν βρέχει makes it sound habitual:

I walk fast in the park when it isn’t raining (whenever that condition is true).

How do you pronounce and stress the words in this sentence?

Word by word:

Περπατάω – per‑pa‑TA‑o
- Stress on the third syllable from the end (τά). The last -ω is like “o” in go but shorter.
γρήγορα – GRI‑go‑ra
- γρ like gr, η = i (as in see), stress on the first syllable.
στο – sto
- Like stoh; short o.
πάρκο – PAR‑ko
- ρ is a tapped/trilled r; stress on πά.
όταν – O‑tan
- Stress on ό; like English OH-tan (shorter vowels).
δεν – then
- δ = “th” in this (voiced), not d.
βρέχει – VRE‑chi
- β = v, ρ = trilled r, ε = e in pet,
- χ is a voiceless guttural (like German “Bach” or Scottish “loch”),
- stress on βρέ.

Overall rhythm:
ΠερπαΤΆω ΓΡΉγορα στο ΠΆρκο Όταν ΔΕΝ ΒΡΈχει.