Jo større dataforbruget er, desto mere betaler jeg.

It is the standard Danish way to express a proportional comparison:

• jo større ..., desto mere ...
• the greater ..., the more ...

It is used when one thing changes together with another. Very often, English uses the + comparative, the + comparative, while Danish uses jo + comparative, desto + comparative.

So this structure means something like:

• as X increases, Y increases
• the more/bigger X is, the more Y happens

In modern Danish, this is a very common pattern to learn as a set phrase.

Because større is the comparative form of stor.

• stor = big
• større = bigger / greater
• størst = biggest / greatest

In this sentence, Danish is comparing levels of data usage, so it needs the comparative form.

The same thing happens with mere:

• meget = much
• mere = more
• mest = most

So both halves of the sentence use comparatives:

• større
• mere

Because Danish usually writes compound nouns as one word.

Here you have:

• data = data
• forbrug = consumption / usage

Together:

• dataforbrug = data usage / data consumption

This is very normal in Danish. English often separates these words, but Danish usually combines them into a single noun.

The ending -et makes the noun definite:

• dataforbrug = data usage
• dataforbruget = the data usage

Danish often adds the definite article as an ending instead of using a separate word like English the.

So instead of saying something like the data usage with a separate article, Danish says dataforbruget.

Because there is no adjective before the noun here, the attached definite ending is the normal choice.

Compare:

• dataforbruget = the data usage
• det store dataforbrug = the big data usage

When there is an adjective, Danish usually uses a separate definite marker too.

This is because the first part follows the word order commonly used in this jo + comparative structure.

A useful way to remember it is:

• Jo + comparative + subject + verb
• Desto/jo + comparative + verb + subject

So:

• Jo større dataforbruget er ...

Here:

• jo større comes first
• dataforbruget is the subject
• er is the finite verb

To an English speaker, the order can feel unusual, but it is the normal Danish pattern in this construction.

Because Danish main clauses follow the V2 rule: the finite verb normally comes in second position.

In the second clause, desto mere is placed first. That means the verb must come next:

• desto mere betaler jeg

Structure:

• first position: desto mere
• second position: betaler
• then the subject: jeg

If you started with the subject instead, you would say:

• Jeg betaler mere

But once desto mere is fronted, inversion happens:

• Desto mere betaler jeg

Yes. In modern Danish, many speakers also use jo ... jo ...:

• Jo større dataforbruget er, jo mere betaler jeg.

This is very common and natural.

So:

• jo ... desto ... = correct, often a bit more formal or traditional
• jo ... jo ... = also correct and very common in everyday Danish

Both patterns are worth recognizing.

Because mere is used for amount or degree, while flere is used for countable plural things.

• mere = more in general amount/degree
• flere = more of several countable items

Here, betaler jeg mere means I pay more, so we are talking about a greater amount of payment, not a greater number of separate objects.

Compare:

• Jeg betaler mere. = I pay more.
• Jeg har flere regninger. = I have more bills.

It is the same spelling, but not the same function.

Danish jo can be used in different ways. For example:

• as a reply meaning something like yes, actually
• as a particle meaning something like after all / you know
• as part of the fixed comparative structure jo ... desto/jo ...

In this sentence, jo is not the reply word. It is part of the grammar pattern that links two comparatives together.

So when you see jo here, think of the whole structure:

• jo større ..., desto mere ...

not the separate everyday jo used in conversation.

Usually it sounds like a general relationship or rule.

The present tense in Danish can be used for general truths, habits, or regular results. So this sentence normally means something like:

• whenever my data usage is higher, I pay more
• there is a direct relationship between usage and cost

It does not have to refer to one single moment. It often sounds like a statement about a phone plan, internet plan, or billing system.