Csatlakozom a bulihoz és táncolok.

Hungarian usually leaves out subject pronouns when they are clear from the verb ending.

• csatlakozom already means I join / I’m joining
• táncolok already means I dance / I’m dancing

So én is not necessary. You would add én only for emphasis, contrast, or clarity:

• Én csatlakozom a bulihoz, nem ő.
  I’m joining the party, not him/her.

Hungarian dictionaries usually list verbs in the 3rd person singular present form, which for this verb is csatlakozik: he/she joins.

When you change the subject to I, the verb changes form:

• csatlakozik = he/she joins
• csatlakozom = I join

So this is just normal verb conjugation.

Because these two verbs belong to different patterns.

• csatlakozik is an -ik verb, and in standard Hungarian many -ik verbs have -om / -em / -öm in the I form.
• táncol is a regular non--ik verb, so its I form is táncolok.

So:

• csatlakozik → csatlakozom
• táncol → táncolok

A learner will see this often in Hungarian, especially with verbs whose dictionary form ends in -ik.

Because csatlakozik does not take a direct object the way join does in English.

In Hungarian, csatlakozik usually goes with the ending -hoz / -hez / -höz, which means something like to, toward, or to the group/event.

So:

• csatlakozom a bulihoz = literally something like I join to the party
• natural English meaning: I join the party

This is a very common thing in language learning: the Hungarian verb uses a different structure than the English one.

-hoz is the allative ending. It usually expresses movement or connection toward something.

Examples:

• a házhoz = to the house
• a csapathoz = to the team
• a bulihoz = to the party

With csatlakozik, this ending is the normal choice.

This is because of vowel harmony, a basic Hungarian pattern.

The suffix has three forms:

• -hoz
• -hez
• -höz

The form depends on the vowels in the word. buli contains the back vowel u, so it takes the back-vowel form:

• buli + hoz = bulihoz

This is one of the most important patterns in Hungarian grammar.

Not with csatlakozom if you want to keep the same meaning.

• a buliba means into the party
• a bulihoz means to the party / joining the party

So:

• Buliba megyek. = I’m going to the party.
• A bulihoz csatlakozom. = I’m joining the party.

The first focuses on going there. The second focuses on joining in.

Hungarian has two forms of the:

• a before a consonant
• az before a vowel

Since bulihoz begins with b, Hungarian uses a:

• a bulihoz

Compare:

• a ház
• az autó

Hungarian word order is much more flexible than English word order. It often depends on focus and emphasis, not just grammar.

Csatlakozom a bulihoz és táncolok. is a natural neutral sentence meaning something like I join the party and dance.

You could move things around, but the emphasis would change:

• A bulihoz csatlakozom és táncolok.
  Puts more attention on the party
• Én csatlakozom a bulihoz és táncolok.
  Puts more attention on I

So the original order is normal and natural.

It can mean either one, depending on context.

Hungarian present tense often covers both:

• I dance
• I am dancing

So táncolok can be:

• habitual: I dance
• current: I’m dancing

The surrounding situation tells you which meaning is intended.

Because here the verb has no direct object.

Hungarian has two main conjugation patterns often called:

• indefinite
• definite

When there is no definite direct object, you normally use the indefinite form:

• táncolok = I dance / I’m dancing

A form like táncolom would only make sense with a definite object, and even then it would be unusual in most everyday contexts.

A rough English-friendly pronunciation is:

CHAWT-lah-ko-zom aw BOO-lee-hoz aysh TAAN-tso-lok

A few useful sound notes:

• cs = ch as in chair
• c = ts as in cats
• s = sh
• é is a long ay-like sound
• stress is usually on the first syllable of each word

So:

• Csatlakozom → starts with ch
• és → sounds like aysh
• táncolok → has ts in the middle

Yes. Buli is a very common everyday word for party, and it feels fairly casual and conversational.

So this sentence sounds natural in normal speech. It is not unusually formal.

In many real-life situations, buli is exactly the word people would use.