У мене болить передпліччя.

Because this is a very common Ukrainian way to talk about pain.

The structure is roughly:

• У мене = at me / with me
• болить = hurts / aches
• передпліччя = forearm

So the sentence is literally something like At me, the forearm hurts, but the natural English translation is My forearm hurts.

In Ukrainian, the person experiencing the pain is often not the grammatical subject. The body part is.

Мене is in the genitive case.

After у / в in this kind of possession-or-experience expression, Ukrainian uses the genitive:

• у мене = I have / my / at me
• у тебе = you have / your
• у нього = he has / his

So in this sentence, у мене does not mean simple location. It functions more like my or I have in English.

Because Ukrainian usually does not need a possessive adjective here.

Instead of saying something like my forearm hurts, Ukrainian normally says:

• У мене болить передпліччя.

This is the most natural everyday pattern for talking about body pain.

You can say:

• Моє передпліччя болить.

But that sounds more marked, more explicit, or more contrastive—like you are stressing that it is my forearm, not someone else’s.

Here передпліччя is in the nominative singular.

It is the grammatical subject of the sentence—the thing that hurts. That is why the verb is also singular:

• передпліччя болить

Even though in English we often think of the person as the main subject, Ukrainian treats the painful body part as the subject in this pattern.

Because передпліччя is singular.

• болить = hurts for a singular thing
• болять = hurt for plural things

Compare:

• У мене болить передпліччя. = My forearm hurts.
• У мене болять руки. = My hands/arms hurt.

So the verb agrees with the body part, not with мене.

Yes. У and в are often interchangeable in Ukrainian.

The choice is usually about sound and flow, not meaning. Ukrainian often alternates between у and в to avoid awkward sound combinations.

So both of these are fine:

• У мене болить передпліччя.
• В мене болить передпліччя.

The meaning stays the same.

Передпліччя means forearm—the part of the arm between the elbow and the wrist.

It does not mean the whole arm.

Some useful contrasts:

• рука = arm / hand (depending on context)
• передпліччя = forearm
• лікоть = elbow
• зап’ястя = wrist

So this sentence is specifically about pain in the forearm.

No, Ukrainian word order is fairly flexible.

The neutral, everyday version is:

• У мене болить передпліччя.

But other orders are possible for emphasis, for example:

• Передпліччя у мене болить.
  This puts more focus on the forearm.

• Болить у мене передпліччя.
  This is also possible, but less neutral.

So the given sentence is the most standard, unmarked way to say it.

The stress is on плі:

• передплі́ччя

A learner may notice the spelling чч. That is pronounced like a longer ch sound, not as two completely separate sounds.

A rough English-friendly guide would be something like:

• pe-red-PLI-chchya

You do not need to overdo it, but it should sound heavier than a single ч.

Yes, grammatically you can.

But in normal everyday Ukrainian, У мене болить передпліччя is more natural.

Use Моє передпліччя болить when you want extra emphasis, for example:

• contrasting with another person
• stressing possession
• speaking more deliberately

So both are correct, but they do not feel equally natural in the same situation.

Structurally, it is closer to My forearm hurts.

That is because передпліччя is the subject, and болить means hurts / aches.

But because of У мене, the whole pattern may also feel a little like I have a hurting forearm or I have pain in my forearm.

So:

• literal structure: At me, the forearm hurts
• natural English meaning: My forearm hurts

That is the best way to understand it.