Learn Hardcore Hungarian: Nyáron gyakran utazunk a tóhoz, mert a barátom szeret ott úszni. - In summer we often travel to the lake because my friend likes to swim there.

The ending -on/-en/-ön (called the superessive case) is often used for time expressions, especially:
- seasons: nyáron, télen, tavasszal, ősszel
- days of the week: hétfőn, kedden, etc.

You usually don’t use an extra preposition like in; the case ending itself means in (that time).

You can say a nyáron in some contexts, but:

Nyáron (without article) means in summer / in the summer (generally, as a habit).
A nyáron is more like this past summer or that particular summer, so it feels more specific.

In your sentence the habitual meaning (In summer we often travel…) is best expressed with nyáron.

Can I change the word order to Gyakran nyáron utazunk a tóhoz? Does it mean the same?

Both word orders are grammatically correct, but the focus/emphasis changes slightly.

Nyáron gyakran utazunk a tóhoz…
Neutral-ish reading: You’re first setting the time frame (in summer), then saying that within that time, you often travel.
Gyakran utazunk nyáron a tóhoz…
Starts with the frequency (often), and then specifies when that often-ness applies. Still natural, just a different information order.

Hungarian word order is flexible, but the focus tends to be just before the verb in neutral sentences. Here, there’s no strong contrast, so several orders are possible. The original one is very typical and natural.

Why is there no subject pronoun, like Mi nyáron gyakran utazunk…?

Hungarian usually drops subject pronouns because the verb ending already shows the person and number:

utazunk = we travel
The ending -unk tells you it’s 1st person plural (we).

You only add mi (we) when you want to:

contrast with someone else:
Mi nyáron utazunk, ők télen. – We travel in summer, they (travel) in winter.
or give extra emphasis.

In a neutral sentence, Nyáron gyakran utazunk… is more natural than Mi nyáron gyakran utazunk….

What exactly does the verb form utazunk tell me?

Utazunk comes from utazni (to travel).

stem: utaz-
person/number ending: -unk

So:

utazunk = we travel / we are travelling
It is present tense, indefinite conjugation, 1st person plural.

It’s indefinite because there is no definite direct object (you’re not “travelling something”, you’re just travelling to somewhere). If there were a definite direct object, you’d use the definite conjugation instead.

What does the ending -hoz in a tóhoz mean, and why not -ba or -ra?

Hungarian has several common “direction” endings:

-hoz / -hez / -höz = to(ward), to the vicinity of
a tóhoz megyünk – we go to the lake (to that place by the lake)
-ba / -be = into (movement into the interior)
a tóba ugrunk – we jump into the lake
-ra / -re = onto (movement onto a surface)
a tóra megyünk is odd in most contexts, but with other nouns:
az asztalra teszem – I put it on(to) the table.

In a tóhoz, you’re describing going (to) the place of the lake, not into the water, so -hoz is appropriate.

The exact form -hoz (and not -hez/-höz) is due to vowel harmony:

tó has a back vowel (ó) → takes the back variant -hoz.

Why do we say a tóhoz, but a barátom? Why is there an article in both?

Hungarian uses articles similarly to English, but with some differences.

a tóhoz
- a = the
- tó = lake
- -hoz = to(ward)
  → to the lake
Here the article a is straightforward: you’re talking about a specific lake.
a barátom
- barát = friend
- -om = my (1st person singular possessive)
- a barátom = my friend
With possessed nouns, Hungarian normally uses the definite article in neutral statements:
- a házam – my house
- a könyvem – my book
- a barátom – my friend

You can omit the article in some special focuses or titles, but a barátom is the standard neutral form for my friend.

What exactly does barátom mean? Why not az én barátom?

Barátom is a single word meaning my friend.

barát = friend
-om = my (1st person singular possessive ending)

So barátom already contains the meaning of my.
Adding én (I) is possible but not necessary, and usually adds emphasis:

a barátom – my friend (neutral)
az én barátom – my friend (as opposed to someone else’s, or emphasizing that it’s mine)

Note that when you add én, you must use az én barátom, because:

én starts with a vowel → the article before it is az, not a:
- a barátom
- az én barátom

How does szeret ott úszni work grammatically? Why szeret + úszni?

Szeret can mean “to like” or “to love”, depending on context.

With an infinitive, szeret + infinitive = likes to (do something):

szeretek olvasni – I like to read / I like reading
szeret zenét hallgatni – he/she likes listening to music

In your sentence:

a barátom szeret ott úszni
= my friend likes to swim there

Here:

szeret is 3rd person singular present
úszni is the infinitive of úszik (to swim)

So the structure is:

[subject] + szeret + [place/time/etc.] + [infinitive]
a barátom szeret ott úszni → my friend likes to swim there

Could I say A barátom ott szeret úszni instead of A barátom szeret ott úszni? Does word order change the meaning?

Both are grammatical, but again the emphasis shifts.

A barátom szeret ott úszni.
Neutral: the main info is that your friend likes to swim there (as an activity and place together).
A barátom ott szeret úszni.
This tends to emphasize ott (there):
It is there that my friend likes to swim (as opposed to somewhere else).

So:

szeret ott úszni → focus more on the activity liking to swim there in general.
ott szeret úszni → highlights the place there as the important detail.

In everyday speech, both are possible; context and intonation decide which feels more natural.

What does ott add in this sentence? Could we just say A barátom szeret úszni?

Ott means “there”, referring to the place you already mentioned: a tóhoz (to the lake).

A barátom szeret úszni.
= My friend likes to swim. (in general, no specific place)
A barátom szeret ott úszni.
= My friend likes to swim there.
That is, at (or in) that lake you just mentioned.

So ott connects the subordinate clause back to the location a tóhoz in the main clause.

Why is there a comma before mert in …, mert a barátom szeret ott úszni.?

In Hungarian, mert (because) typically introduces a subordinate clause of reason, and it is normally preceded by a comma, just like “because” often is in English:

Nyáron gyakran utazunk a tóhoz, mert a barátom szeret ott úszni.
In summer we often travel to the lake, because my friend likes to swim there.

Pattern:

[main clause] , mert [reason clause]

You could also reverse the order (still with a comma):

Mert a barátom szeret ott úszni, nyáron gyakran utazunk a tóhoz.
Because my friend likes to swim there, we often travel to the lake in summer.

Where can gyakran go in the sentence, and does its position matter?

Gyakran means “often”, and it’s quite flexible in word order. Some common positions:

Nyáron gyakran utazunk a tóhoz…
Gyakran nyáron utazunk a tóhoz…
Nyáron utazunk gyakran a tóhoz… (less neutral, more marked/emphatic)

All can be understood, but the most neutral and natural positions are:

Nyáron gyakran utazunk a tóhoz…
Gyakran utazunk nyáron a tóhoz…

In very general terms:

Put gyakran early in the clause to state frequency in a neutral way.
Moving it around can highlight or contrast different parts of the sentence, but for a learner, sticking to [time] + gyakran + [verb] is a safe default.