Learn Hardcore Hungarian: A barátom barátai ma a parkban sétálnak. - My friend's friends are walking in the park today.

specific people or things already known from context
specific locations (like a parkban – in the park)
specific possessed nouns (A barátom barátai – my friend’s friends = the friends of my friend)

So here, A barátom barátai = The friends of my friend.

What is the difference between barátom and barátai, and what does A barátom barátai mean exactly?

These are both based on barát (friend), but they show different possession and number:

barátom = my friend
- barát (friend) + -om (my) → my friend (singular)
barátai = (his/her) friends
- barát (friend) + -ai (plural possessed) → friends belonging to someone

Put together:

A barátom barátai = my friend’s friends
- literally: the friends of my friend

So:

barátom: my friend
barátai: his/her friends
A barátom barátai: my friend’s friends

How would I say my friends (plural), as opposed to my friend’s friends?

For my friends (plural) you use a different ending:

barátom = my friend (one friend)
barátaim = my friends (more than one friend)

Forms side by side:

barátom – my friend
barátaim – my friends
A barátom barátai – my friend’s friends (the friends belonging to my friend)

So if you wanted to say My friends are walking in the park today, you’d say:

A barátaim ma a parkban sétálnak.

Why is there no separate word for “are” in sétálnak?

Hungarian does not use a separate verb like am/is/are with ordinary verbs in the present tense.

The information that English puts into “are walking” is all inside sétálnak:

sétál- = the verb stem to walk
-nak = marks 3rd person plural (they)

So sétálnak means “they walk / they are walking”, depending on context.
Hungarian simply uses the present tense form of the verb without an extra “are”.

What does the -nak ending on sétálnak tell me?

The -nak / -nek ending here is a verb ending that shows:

person: 3rd person
number: plural (they)
tense: present tense
conjugation type: indefinite (because there is no definite object, like them / it being walked)

Compare:

Ő sétál. – He/She walks / is walking. (3rd person singular)
Ők sétálnak. – They walk / are walking. (3rd person plural → -nak)

In A barátom barátai … sétálnak, the subject (A barátom barátai) is plural, so the verb must be plural too: sétálnak.

Why does parkban mean “in the park”? What is the -ban ending?

-ban / -ben is the inessive case ending, meaning “in / inside”.

park = park
parkban = in the park

General pattern:

ház – house → házban – in the house
város – city → városban – in the city
iskola – school → iskolában – in the school

The article makes it a parkban = in the park (specific park).
Without the article, parkban would be more like in a park / in parks (in general), depending on context.

Why is it parkban and not parkben if the ending is -ban / -ben?

The choice between -ban and -ben is based on vowel harmony, not on the consonant:

With back vowels (a, á, o, ó, u, ú): use -ban
With front vowels (e, é, i, í, ö, ő, ü, ű): use -ben

The word park has a, a back vowel, so it takes -ban:

park → parkban (in the park)
kert (garden, has e) → kertben (in the garden)

Why do we say a parkban and not just parkban? Do we always need an article before places?

You don’t always need an article before a place word, but you often do when you mean a specific place.

a parkban – in the park (a particular park, known from context)
parkban sétálnak – they walk in (a) park(s) / in parks (more general, depends on context)

Typically you use a / az:

before a specific place: a parkban, az iskolában, a városban
before a specific person/thing: a barátom, a könyv, az autó

No article is used with many time expressions (like ma = today, holnap = tomorrow), but locations usually do take an article when you’re talking about a particular, known one.

Can I change the order of ma and a parkban? For example, can I say Ma a parkban sétálnak?

Yes. Both are possible, but the neutral/typical order in everyday speech for this simple sentence is:

A barátom barátai ma a parkban sétálnak.
Subject – time – place – verb

If you say:

Ma a parkban sétálnak a barátom barátai.

you put a bit more emphasis on Ma a parkban (Today, in the park, they walk…), and the subject comes at the end.

You can also say:

A barátom barátai a parkban ma sétálnak.

This is grammatically correct but sounds more marked, with a special emphasis (e.g. It’s today that they are walking in the park).

For a learner, it’s safest to stick to:

[Subject] + ma + [place] + [verb]
→ A barátom barátai ma a parkban sétálnak.

How is the tense understood? Does sétálnak mean “walk” or “are walking” or “will walk”?

Hungarian has one present tense, and context decides whether English uses:

simple present (walk)
present continuous (are walking)
near future (are going to walk / will walk)

In A barátom barátai ma a parkban sétálnak:

it could mean they are currently walking there today
or it could also be used for a planned event today, like My friend’s friends are going to walk in the park today.

Hungarian often uses the present tense with a time word (ma, holnap, jövő héten) where English uses a future form:

Holnap a parkban sétálnak. – They will walk / are going to walk in the park tomorrow.

How would I negate this sentence? How do I say “are not walking”?

To negate a verb in Hungarian, you put nem in front of the verb.

So:

A barátom barátai ma a parkban sétálnak.
→ My friend’s friends are walking in the park today.

Negated:

A barátom barátai ma a parkban nem sétálnak.
→ My friend’s friends are not walking in the park today.

The position before the verb is crucial:

nem sétálnak = do not walk / are not walking
Everything else in the sentence stays the same.