Перед пранням я люблю сортувати білизну за кольором.

Because білизну is the accusative singular form of білизна.

In this sentence, білизна is the direct object of сортувати (to sort), so Ukrainian uses the accusative:

• білизна = nominative, dictionary form
• білизну = accusative singular

This is very common in Ukrainian. Compare:

• Я бачу книгу. = I see a book.
• Я сортую білизну. = I sort the laundry.

So the ending changes because the noun is receiving the action.

Here білизна means laundry.

Depending on context, білизна can also mean things like:

• linen
• underwear
• bed linen

But in a sentence about washing and sorting by color, the natural meaning is laundry.

So this is one of those words whose exact translation depends on context.

Пранням is in the instrumental case.

The preposition перед often means before / in front of, and when it is used with nouns, it normally takes the instrumental case.

So:

• прання = washing, laundry, the act of washing
• пранням = instrumental singular

That gives:

• перед пранням = before washing

A few similar examples:

• перед уроком = before the lesson
• перед сном = before sleep / before going to sleep
• перед вечерею = before dinner

So the form is not random: it is required by перед.

Here за means something like by, according to, or on the basis of.

In this meaning, за commonly takes the instrumental case, so:

• колір = color
• кольором = instrumental singular

So:

• сортувати за кольором = to sort by color

This is a very useful pattern. You can also say things like:

• за розміром = by size
• за алфавітом = alphabetically / by alphabet
• за номером = by number

So за кольором does not literally mean behind color here. It is a different meaning of за.

Прання is a noun, not a finite verb.

It comes from the idea of washing, and in this sentence it means washing / laundry / the washing process.

You can think of it like an English -ing noun:

• прати = to wash
• прання = washing

So:

• Перед пранням = Before washing

Ukrainian often uses these verbal nouns where English might use either a noun or an -ing form.

Люблю means I love / I like, and it is followed by an infinitive: сортувати (to sort).

So the structure is:

• я люблю сортувати = I like to sort

This is very normal in Ukrainian. Compare:

• Я люблю читати. = I like to read.
• Я люблю готувати. = I like to cook.
• Я люблю подорожувати. = I like to travel.

English can say both I like sorting and I like to sort. Ukrainian usually uses любити + infinitive in this kind of sentence.

Сортувати is the imperfective verb, and that fits well here because the sentence describes a habit or a general preference.

The speaker is saying that this is something they like to do in general, not talking about one single completed act.

Imperfective is commonly used for:

• habits
• repeated actions
• general statements
• processes

So:

• я люблю сортувати білизну = I like sorting laundry / I like to sort laundry

If you used a perfective form, it would sound more like focusing on completing a particular sorting action, which is not the main idea here.

It could be omitted.

Ukrainian often drops subject pronouns when the verb already makes the subject clear. Since люблю clearly means I love / I like, you can say:

• Перед пранням люблю сортувати білизну за кольором.

That still means Before washing, I like to sort the laundry by color.

Including я is also completely correct. It can make the sentence a little clearer, a little more explicit, or slightly more contrastive.

So both are natural:

• Перед пранням я люблю сортувати білизну за кольором.
• Перед пранням люблю сортувати білизну за кольором.

Yes. Ukrainian word order is fairly flexible.

The original sentence is perfectly natural, but you could also hear variations like:

• Я люблю перед пранням сортувати білизну за кольором.
• Білизну я люблю сортувати за кольором перед пранням.

However, the original order is a very neutral and natural one:

• Перед пранням sets the time frame first
• я люблю gives the subject and main verb
• сортувати білизну за кольором gives the action and the criterion

So yes, the order can change, but not all versions sound equally neutral.

Sometimes, yes, but перед пранням is the most natural choice here.

• перед пранням = before washing
• до прання = before washing / prior to washing

Both can be understood, but перед + instrumental is a very common everyday way to express before in time.

So if you are describing a routine action in ordinary speech, перед пранням is an excellent choice.

A helpful stress guide is:

• пере́д
• пра́нням
• я
• люблю́
• сортува́ти
• біли́зну
• за
• ко́льором

A rough English-style approximation would be:

• peh-RED PRAN-nyam ya lyu-BLYU sor-too-VA-ty bi-LYZ-nu za KO-ly-rom

A few pronunciation notes:

• я is pronounced like ya
• люблю has a soft lyu sound
• нь in пранням is soft
• білизну has stress on the -лиз- part
• кольором starts with ko-, with stress on the first syllable

If you want to sound natural, pay special attention to the stressed syllables.