Я мию волосся шампунем, а потім сушу його феном.

In Ukrainian, волосся is a collective noun and is grammatically neuter singular, even though in English hair can feel like a mass noun or sometimes something plural-like in meaning.

So in this sentence:

• Я мию волосся = I wash my hair

You do not usually say мої волосся for my hair. Since волосся is singular neuter, it would agree like a singular neuter noun.

This is also why later the sentence uses його = it, not them.

Because волосся is grammatically singular neuter in Ukrainian.

So:

• волосся → neuter singular
• the pronoun referring back to it is його = it

In English, we do not usually say I dry it with a hairdryer when talking about hair, but in Ukrainian that grammar is completely normal:

• сушу його = I dry it

So this is a case where you should follow Ukrainian grammar, not English logic.

They are in the instrumental case.

The instrumental case is often used for the tool, means, or instrument used to do something. In this sentence:

• шампунем = with shampoo / using shampoo
• феном = with a hairdryer / using a hairdryer

Compare:

• шампунь → nominative

• шампунем → instrumental

• фен → nominative
• феном → instrumental

So:

• мию шампунем = I wash with shampoo
• сушу феном = I dry with a hairdryer

This is a very common use of the instrumental case in Ukrainian.

Not here.

Ukrainian often uses the instrumental case without a preposition to mean with / by means of / using.

So:

• мию волосся шампунем = I wash my hair with shampoo
• сушу його феном = I dry it with a hairdryer

If you added з here, it would usually sound like together with rather than using.

So in this sentence, the no-preposition instrumental is the natural choice.

Мию is the ordinary verb form I wash.

Here, the object is explicitly stated:

• Я мию волосся = I wash my hair

The reflexive form митися means to wash oneself / to be washing oneself. It is possible in some contexts, but it changes the focus:

• Я миюся = I am washing myself
• Я мию волосся = I wash my hair

Since the sentence specifically talks about hair, the non-reflexive verb мити is the natural choice.

Because in Ukrainian, possession is often understood from context.

If you say:

• Я мию волосся

it naturally means I wash my hair, not someone else’s hair, unless the context suggests otherwise.

You can add моє only if you want to emphasize it, but that is often unnecessary:

• Я мию своє волосся = I wash my own hair / my hair specifically

So the sentence sounds natural without a possessive adjective.

потім means then / afterwards.

The word а here links the two actions and often has the sense of and then / while / and after that, depending on context.

So:

• Я мию волосся шампунем, а потім сушу його феном.
• I wash my hair with shampoo, and then dry it with a hairdryer.

Why а and not just і?

• і = simple and
• а often marks a slight transition or contrast, or moves to the next step in a sequence

In this sentence, а потім sounds very natural because it introduces the next action.

It can mean either, depending on context.

Ukrainian present-tense forms often cover both:

• I dry
• I am drying

So:

• сушу can mean I dry or I am drying
• мию can mean I wash or I am washing

In a sentence like this, English often uses the simple present for a routine:

• I wash my hair with shampoo, then dry it with a hairdryer

But it could also describe what someone is doing right now, depending on context.

The dictionary forms are:

• мити = to wash
• сушити = to dry

The forms in the sentence are first person singular present:

• я мию = I wash / I am washing
• я сушу = I dry / I am drying

So the pattern is:

• мити → мию
• сушити → сушу

These are common verbs worth memorizing.

The given word order is natural, but Ukrainian word order is fairly flexible.

Neutral version:

• Я мию волосся шампунем, а потім сушу його феном.

You could move things around for emphasis, for example:

• Шампунем я мию волосся, а потім феном сушу його.

That sounds more marked, because it emphasizes the tools.

For most learners, the original order is the safest and most natural: subject + verb + object + instrument.

Ukrainian has no articles like a and the.

So феном by itself does not tell you whether it is:

• with a hairdryer
• with the hairdryer

English chooses the article based on context. In a general sentence about routine actions, with a hairdryer is usually the most natural translation.

The same is true for many Ukrainian nouns: article choice appears only when translating into English.

Usually, for hair on the head in a general sense, волосся is the normal word.

волоси is the plural form of волос and is used in some contexts, but for everyday phrases like wash one’s hair, comb one’s hair, dry one’s hair, learners should strongly prefer волосся.

So:

• мити волосся = standard, natural
• мити волоси = not the usual choice here

By itself, it can be either.

Ukrainian present tense does not force the same distinction English sometimes makes. So the sentence can mean:

• a routine: I wash my hair with shampoo, then dry it with a hairdryer
• a current action, if the context supports it: I’m washing my hair with shampoo and then drying it with a hairdryer

If you want to know which meaning is intended, you usually look at the wider context, not just the verb form.