Learn Hardcore Hungarian: A bőrönd tele van ruhával, ezért nehezen visszük fel a lépcsőn. - The suitcase is full of clothes, so we carry it up the stairs with difficulty.

The ending -val / -vel on ruhával is the instrumental-comitative case.
With tele (van), Hungarian often uses this case to mean “full of X”:

tele van ruhával – full of clothes
tele van vízzel – full of water
tele van emberekkel – full of people

Literally it’s closer to “full with clothes”, but in idiomatic English we translate it as “full of clothes”.

So:

ruha = clothes / a piece of clothing
ruhával = “with clothes” → in this construction: “of clothes”

Why is “ruha” in the singular (ruhával), not plural like “ruhákkal”?

Both are possible, but there’s a nuance:

ruhával (singular) – treats “clothing” more like a mass or an uncountable substance.
- “full of clothing / full of clothes (in general)”
ruhákkal (plural) – emphasizes individual items of clothing.
- “full of (lots of) clothes / many garments”

So you could also say:

A bőrönd tele van ruhákkal. – equally correct, a bit more “item-focused”.

The original ruhával is perfectly natural and doesn’t sound wrong to natives.

Why is the word order “A bőrönd tele van ruhával” and not “A bőrönd ruhával tele van”?

Both are grammatical, but the neutral and most usual word order for this meaning is:

A bőrönd tele van ruhával. – neutral: “The suitcase is full of clothes.”

The variant:

A bőrönd ruhával tele van.

is also possible and can sound a bit more emphatic on what it is full of:

Roughly: “The suitcase is full with clothes (as opposed to something else).”

So:

[A bőrönd] [tele van] [ruhával]. – “The suitcase is full of clothes.” (normal)
[A bőrönd] [ruhával] [tele van]. – slight focus on ruhával (“with clothes”).

What does “ezért” mean here, and why is there a comma before it?

ezért is a conjunctive adverb meaning “therefore, so, for that reason”.

The sentence has two independent clauses:

A bőrönd tele van ruhával,
ezért nehezen visszük fel a lépcsőn.

In Hungarian, when you join two full clauses with ezért, you usually put a comma before it:

…, ezért … = “…, therefore …” / “…, so …”

So it works like:

A bőrönd tele van ruhával, ezért (mi) nehezen visszük fel a lépcsőn.
– “The suitcase is full of clothes, so we have difficulty carrying it up the stairs.”

Why is it “nehezen” and not “nehéz” in the second part?

nehéz = heavy / difficult (adjective)
nehezen = with difficulty, hardly (adverb)

In the second clause we’re describing how we carry it (the manner of the action), so we need an adverb:

nehezen visszük fel – “we carry it up with difficulty / it’s hard for us to carry it up”

If you used nehéz, that would be an adjective and would need a different structure, e.g.:

A bőrönd nehéz, ezért nehezen visszük fel a lépcsőn.
– “The suitcase is heavy, so we carry it up with difficulty.”

So nehezen is correct because it modifies the verb (“carry”), not the suitcase itself.

What is going on with “visszük”? How is this form built, and why not “viszünk”?

The verb is vinni (“to carry, to take”), stem visz-.

It has two conjugations:

Indefinite (no specific/definite object):
- viszek, viszel, visz, viszünk, visztek, visznek
Definite (definite object: it / the suitcase / that thing, etc.):
- viszem, viszed, viszi, visszük, viszitek, viszik

In our sentence, there is a definite object understood from context: “it” = the suitcase.

So Hungarian uses the definite form:

visszük = “we carry it” / “we are taking it”

If the sentence were about carrying something unspecific, we’d use indefinite:

Viszünk valamit. – We are taking/carrying something.
Visszük a bőröndöt. – We are taking the suitcase (definite).

The spelling visszük (with ssz) comes from sound changes: visz + jük → visszük.

Why is the direct object (“the suitcase”, “it”) not written in the second clause?

Hungarian often omits pronouns or repeated nouns when they are obvious from context.

First clause:

A bőrönd tele van ruhával… – We’re talking about “the suitcase”.

Second clause:

… ezért nehezen visszük fel a lépcsőn.

Here visszük is in the definite form, which already signals “we carry it / the known thing”.
So the listener understands:

“we carry it up the stairs with difficulty” = we carry the suitcase.

You could say explicitly:

… ezért nehezen visszük fel a bőröndöt a lépcsőn.

This is also correct, just a bit more repetitive; everyday speech happily leaves the object implied.

Why is it “visszük fel” instead of “felvisszük”? Isn’t the prefix normally before the verb?

Hungarian verbal prefixes (like fel-) indeed usually stand before the verb:

felvisszük – “we take it up”

However, when another word is in focus before the verb, the prefix is typically pushed after the verb.
In this sentence, the focus is on nehezen (“with difficulty”), which comes immediately before the verb:

focus slot: nehezen
verb: visszük
prefix moves: fel

So you get:

nehezen visszük fel – “we with difficulty carry it up”

If you said:

Felvisszük a lépcsőn. – neutral: “We take it up the stairs.”
Nehezen felvisszük a lépcsőn. – sounds odd; the focus and prefix positions clash.

So the order nehezen visszük fel is the natural one with focus on how we carry it.

What does “fel” add to the meaning? How is it different from just “visszük a lépcsőn”?

vinni = to carry / to take
felvinni = to take up (somewhere)
fel = “up” (as a verbal prefix)

Without fel, visszük a lépcsőn would be vague: “we carry it on the stairs / along the stairs”.
With fel, it clearly means movement upwards:

visszük a lépcsőn – we are carrying it on the stairs (no direction specified)
felvisszük a lépcsőn / visszük fel a lépcsőn – we carry it up the stairs.

So fel adds the idea of “upward direction”.

Why is it “a lépcsőn” with -n, and not something like “a lépcsőre”?

The ending -n is the superessive case: it usually means “on” (on a surface):

a lépcsőn – on the stairs
az asztalon – on the table
az úton – on the road

Hungarian often uses the superessive for motion along a surface as well:

felmegyek a lépcsőn – I go up the stairs (lit. “I go up on the stairs”)
futunk az utcán – we run on the street

-ra/-re is more like “onto” (toward the top/surface as a destination):

a lépcsőre lépek – I step onto the stairs.
A könyvet az asztalra teszem. – I put the book onto the table.

Here, “fel … a lépcsőn” means “up the stairs” (along them), so -n is the natural choice.

Can I change the word order in the second clause, like “Felvisszük nehezen a lépcsőn”?

You can change the word order, but it changes naturalness and sometimes focus.

Some variants and their feel:

Nehezen visszük fel a lépcsőn. – natural, focus on nehezen:
“We carry it up the stairs with difficulty.”
Felvisszük a lépcsőn. – neutral, just states the action:
“We take it up the stairs.”
A lépcsőn visszük fel, nehezen. – possible, but a bit marked or stylistic, with extra emphasis or contrast.
Felvisszük nehezen a lépcsőn. – sounds awkward to most natives; the position of nehezen is odd.

General rule:
The most natural, spoken-Hungarian version with your content and emphasis is exactly:

… ezért nehezen visszük fel a lépcsőn.

How would the sentence change if the subject were “I” instead of “we”?

You would just change the verb to 1st person singular, keeping the same structures:

A bőrönd tele van ruhával, ezért nehezen viszem fel a lépcsőn.
– “The suitcase is full of clothes, so I carry it up the stairs with difficulty.”

Pattern:

visszük (1pl definite) → viszem (1sg definite)
everything else remains the same.