Što se tiče mobilnih podataka, potrošnja je velika.

Što se tiče is a very common Serbian expression meaning as for, regarding, when it comes to, or concerning.

So:

• Što se tiče mobilnih podataka... = As for mobile data...
• It introduces the topic before the main statement.

Grammatically, this expression is fixed, so learners usually memorize it as a whole. You do not normally translate it word-for-word when speaking naturally.

After što se tiče, Serbian normally uses the genitive case.

That is why you get:

• mobilni podaci = mobile data in the dictionary/basic form
• mobilnih podataka = genitive form

So:

• Što se tiče mobilnih podataka = regarding mobile data

This is one of those patterns worth memorizing:

• što se tiče + genitive

Examples:

• Što se tiče vremena, sutra će biti bolje.
• Što se tiče posla, sve je u redu.

Because after što se tiče, you need the genitive, not the accusative.

Compare:

• Vidim mobilne podatke would be accusative plural
• Što se tiče mobilnih podataka is genitive plural

The adjective has to match the noun, so both words change:

• mobilni podaci → mobilnih podataka

This agreement is completely normal in Serbian: adjective and noun match in case, number, and gender.

In Serbian, podaci is normally treated as a plural noun meaning data.

Its singular is:

• podatak = a piece of data / a data point

Its plural is:

• podaci = data

So in this sentence:

• mobilnih podataka = of mobile data

Even though English sometimes treats data like a mass noun, Serbian usually uses the plural noun podaci.

The basic form is potrošnja, meaning consumption, usage, or spending, depending on context.

Here it is the subject of the sentence:

• potrošnja je velika = the usage/consumption is high

Because potrošnja is:

• singular
• feminine

the verb is:

• je = is

And the adjective is:

• velika = feminine singular form of big / high / large

So all of this matches correctly:

• potrošnja → feminine singular
• je
• velika

Because velik changes form to agree with the noun it describes.

Here the noun is:

• potrošnja — feminine singular

So the adjective must also be feminine singular:

• masculine: velik
• feminine: velika
• neuter: veliko

That is why the sentence says:

• potrošnja je velika

If the noun were masculine, you would use velik. If it were neuter, you would use veliko.

Yes. Velik / velika / veliko literally means big, large, or great, but in many contexts it naturally corresponds to English high.

So:

• potrošnja je velika = usage is high
• not necessarily usage is big in natural English

This is very common in Serbian. A word that literally means big may be the normal choice where English prefers high.

Yes. Serbian has several ways to say regarding / when it comes to.

For example:

• Što se tiče mobilnih podataka...
• Kad je reč o mobilnim podacima...
• Što se mobilnih podataka tiče... — also possible, a slight variation in word order

These are similar in meaning, though style and frequency may vary a bit.

A useful thing to notice:

• što se tiče takes genitive
• kad je reč o takes locative, so you would say o mobilnim podacima

So the structure changes depending on the expression.

In many varieties of Serbian, što and šta can both mean what, but in this fixed expression, što se tiče is the normal form.

So learners should treat što se tiče as the standard phrase.

You may hear regional variation in other contexts, but for this expression, it is best to learn:

• Što se tiče...

as a set phrase.

Because the opening phrase Što se tiče mobilnih podataka functions like a topic-setting introductory expression.

The comma separates that introductory part from the main clause:

• Što se tiče mobilnih podataka,
• potrošnja je velika.

This is similar to English punctuation in sentences like:

• As for mobile data, usage is high.

Yes. Serbian word order is fairly flexible.

The given sentence is very natural:

• Što se tiče mobilnih podataka, potrošnja je velika.

But other versions are possible, depending on emphasis:

• Potrošnja je velika što se tiče mobilnih podataka.
• Što se mobilnih podataka tiče, potrošnja je velika.

The original version is probably the clearest and most neutral for a learner. It presents the topic first, then gives the comment about it.

Potrošnja is a very natural word here. It often means consumption or usage, especially for things like:

• electricity
• fuel
• internet or mobile data
• money

Depending on context, Serbian could also use other expressions, but potrošnja is completely normal in a sentence about mobile data.

For example:

• Potrošnja interneta je velika.
• Potrošnja goriva je velika.

So it is a useful word to learn.

Here are the main words in their basic forms:

• što se tiče = fixed expression meaning regarding / as for
• mobilni = mobile
• podatak = piece of data
• podaci = data
• potrošnja = consumption / usage
• biti = to be
• velik = big / large / high

And here is how some of them appear in the sentence:

• mobilni podaci → mobilnih podataka
• velik → velika

This is a good example of how Serbian changes word forms depending on grammar.