A barátnőm ma este ki akarja mosni a ruhákat.

In Hungarian, possession is usually shown with a suffix on the noun instead of a separate word like my.

• barátnő = girlfriend / female friend
• barátnőm = my girlfriend

The ending -m marks 1st person singular possessor: my.

So Hungarian often says:

• barátom = my boyfriend / my male friend
• testvérem = my sibling
• házam = my house

You can also add az én for emphasis, but normally it is not needed:

• (Az én) barátnőm = my girlfriend

ma este means this evening / tonight.

• ma = today
• este = evening

Together, they mean today in the evening, which English usually expresses as tonight or this evening.

Hungarian often uses simple time expressions like this without extra prepositions:

• ma reggel = this morning
• ma délután = this afternoon
• ma este = tonight / this evening

Because akarja is the definite conjugation form of the verb akar (to want).

Hungarian has two main conjugation patterns for many verbs:

• indefinite conjugation: used when there is no definite object, or the object is nonspecific
• definite conjugation: used when the verb has a definite object

In this sentence, the object is a ruhákat = the clothes, which is definite, so Hungarian uses the definite form:

• akar = he/she wants
• akarja = he/she wants it / wants the specific thing

Here it means: she wants to wash the clothes.

Compare:

• Ruhákat akar mosni. = She wants to wash clothes. (indefinite / nonspecific)
• A ruhákat akarja mosni. = She wants to wash the clothes. (definite / specific)

Good question. The basic verb is kimosni, which means to wash out / wash completely / wash clean.

So the infinitive is:

• mosni = to wash
• kimosni = to wash out / to wash clean

But in Hungarian, verbal prefixes like ki- often get separated from the verb when another verb comes before it, such as akar (want).

So:

• Kimossa a ruhákat. = She washes the clothes.
• Ki akarja mosni a ruhákat. = She wants to wash the clothes.

This separation is very common in Hungarian:

• megírni → meg akarja írni = wants to write it
• elolvasni → el akarja olvasni = wants to read it
• felvenni → fel akarja venni = wants to put it on / pick it up

ki- often adds the idea of out, thoroughly, or completely. With washing, kimosni usually means to wash something properly / to wash it out / to get it washed clean.

So:

• mosni = to wash
• kimosni = to wash out / wash clean / do the washing of something

In everyday usage, kimosni a ruhákat is a very natural way to say wash the clothes / do the laundry.

Without the prefix, mosni is still understandable, but kimosni often sounds more complete and idiomatic in this kind of sentence.

Because the noun is both definite and plural, and it is also the direct object.

Let’s break it down:

• a = the
• ruhák = clothes
• ruhákat = clothes + direct object ending

More exactly:

• ruha = piece of clothing / garment
• ruhák = clothes
• ruhákat = clothes (as the object)

The ending -t marks the accusative (direct object), and in the plural form here it appears as -kat.

So:

• a ruhák = the clothes
• a ruhákat = the clothes (as what she wants to wash)

Hungarian marks the direct object with an accusative ending, usually -t.

In this sentence, the thing being washed is the clothes, so ruhákat gets the object marking.

Examples:

• Látom a kutyát. = I see the dog.
• Olvasom a könyvet. = I am reading the book.
• Mosom a ruhákat. = I am washing the clothes.

English mostly shows the object by word order. Hungarian often shows it with an ending on the noun.

Yes, Hungarian word order is flexible, but it is not random. It often changes to show focus, emphasis, or what is already known.

This sentence in its given form is a neutral, natural statement:

• A barátnőm = topic: my girlfriend
• ma este = time
• ki akarja mosni a ruhákat = what she wants to do

You could rearrange it, but the emphasis changes:

• Ma este a barátnőm ki akarja mosni a ruhákat.
  = Tonight, my girlfriend wants to wash the clothes.

• A ruhákat akarja ki mosni ma este a barátnőm.
  = It’s the clothes that my girlfriend wants to wash tonight.
  (more marked, more emphasis)

So the given version is a good default sentence order.

Because Hungarian uses the infinitive after akar (to want), just like English uses to + verb.

• akar = want
• mosni = to wash

So:

• akar mosni = wants to wash
• akarja mosni = wants to wash it / wants to wash the specific thing

This is very similar to English:

• She wants to wash the clothes.

Other examples:

• Akarok aludni. = I want to sleep.
• Akar tanulni. = He/she wants to study.
• Akarjuk látni. = We want to see it.

By itself, barátnőm can mean either:

• my girlfriend
• my female friend

The exact meaning depends on context.

In many real-life situations, Hungarian speakers may use:

• a barátnőm for my girlfriend
• egy barátnőm for a female friend of mine

But context is very important. If the meaning shown to the learner is my girlfriend, then that is the intended reading here.

Yes, but the meaning would change.

• a ruhákat = the clothes, specific clothes
• ruhákat = clothes, some clothes, clothes in general

Compare:

• Ki akarja mosni a ruhákat. = She wants to wash the clothes.
• Ruhákat akar mosni. = She wants to wash clothes / some clothes.

Leaving out a usually makes the object indefinite or less specific, and that would also normally affect the verb form:

• akarja with a definite object
• akar with an indefinite object

So these pair naturally:

• a ruhákat akarja mosni
• ruhákat akar mosni

When a verb with a prefix is used with another verb like akar, the prefix usually stands separately in front of the finite verb, and the main verb appears as an infinitive later.

So Hungarian normally says:

• ki akarja mosni

rather than:

• akarja kimosni

The separated structure is the standard one in this kind of sentence.

Think of the base verb as kimosni, but in this construction it gets split:

• ki
  • akarja
    • mosni

This is one of the very common patterns learners need to get used to in Hungarian.