З одного боку, роумінг потрібний, з іншого боку, тарифікація складна.

Yes. It is a very common paired expression meaning on the one hand ... on the other hand.

Literally, it is something like from one side ... from the other side, but in normal English you should understand it as a contrastive phrase used to present two sides of an issue.

So in this sentence, the speaker is weighing two considerations:

• one side: роумінг потрібний
• the other side: тарифікація складна

Because the preposition з here means from and requires the genitive case.

The dictionary form is бік = side.
After з, it changes:

• бік → nominative
• боку → genitive

So:

• з одного боку = from one side / on the one hand
• з іншого боку = from the other side / on the other hand

This is a good phrase to learn as a whole chunk.

They are also in the genitive singular masculine/neuter form, because they agree with боку, which is in the genitive after з.

Breakdown:

• один → одного
• інший → іншого
• бік → боку

So the whole phrase is grammatically aligned in the genitive:

• з одного боку
• з іншого боку

In Ukrainian, the verb to be is usually omitted in the present tense.

So:

• роумінг потрібний literally looks like roaming necessary
• тарифікація складна literally looks like billing/tariffing complicated

But in natural English, you translate them with is:

• Роумінг потрібний = Roaming is necessary
• Тарифікація складна = Tariffication/Billing is complicated

This omission is completely normal in Ukrainian.

Because adjectives in Ukrainian agree with the noun in gender, number, and case.

Here:

• роумінг is masculine singular, so the adjective is потрібний
• тарифікація is feminine singular, so the adjective is складна

So the pattern is:

• masculine noun + masculine adjective
  роумінг потрібний
• feminine noun + feminine adjective
  тарифікація складна

This kind of agreement is one of the most important features of Ukrainian grammar.

Yes, very often you can. Both are possible, though they can sound a little different in style.

• потрібний is the full adjective form
• потрібен is a shorter predicative form that is very common in statements like X is necessary / needed

So you may hear:

• Роумінг потрібний
• Роумінг потрібен

Both are understandable and correct. In everyday speech, many speakers would find потрібен especially natural in this kind of sentence.

It is a loanword from English and usually refers to mobile phone roaming.

In Ukrainian, роумінг is treated as a masculine noun, which is why it takes:

• потрібний
• or потрібен

So although the word comes from English, it behaves like a normal Ukrainian noun in the sentence.

Тарифікація usually refers to tariff calculation, billing, charging, or the way charges are determined.

Depending on context, English translations might include:

• billing
• pricing
• tariff calculation
• rate-setting

In this sentence, the idea is that the charging/billing system is complicated.

It is a feminine noun, which is why the adjective is складна.

The commas mark the contrastive introductory phrases:

• З одного боку,
• з іншого боку,

These function a bit like discourse markers in English:

• On the one hand,
• on the other hand,

The commas help separate those framing phrases from the main statements:

• роумінг потрібний
• тарифікація складна

In writing, this punctuation is very normal.

Yes, it could. Since the sentence joins two balanced clauses, a semicolon can work well in formal writing:

• З одного боку, роумінг потрібний; з іншого боку, тарифікація складна.

That punctuation makes the contrast even clearer. But the version with commas is also natural and correct.

Not completely. Ukrainian word order is fairly flexible, but the given version is very natural because it clearly sets up the contrast first:

• З одного боку, роумінг потрібний, з іншого боку, тарифікація складна.

You could move parts around for emphasis, but not every rearrangement sounds equally natural. For a learner, the safest choice is to keep this structure as a model:

• contrast phrase
• statement
• contrasting phrase
• second statement

Yes. You can use з одного боку by itself if the other side is understood from context or will appear later.

For example:

• З одного боку, це зручно. = On the one hand, this is convenient.

But very often it is paired with:

• з іншого боку

So for learners, it is helpful to remember the full pair together.

They are:

• роумінг — masculine
• тарифікація — feminine

You can see this from the adjective agreement:

• роумінг потрібний → masculine adjective
• тарифікація складна → feminine adjective

Recognizing noun gender is important because it affects adjectives, pronouns, and sometimes verb forms in the past tense.