La facture de régularisation change la mensualité.

In une facture de régularisation, the phrase de + noun often works like for / of / related to in English.

So facture de régularisation means something like:

• adjustment bill
• regularization invoice
• bill for balancing the account

French often uses de without an article when the second noun describes the type or purpose of the first noun.

Compare:

• une salle de classe = a classroom
• une tasse de café = a cup of coffee
• une facture de régularisation = an adjustment bill

If you said de la régularisation, it would sound more like of the regularization, which is not the normal fixed expression here.

Régularisation is a noun from régulariser, meaning to adjust, to bring into order, or to settle the difference.

In billing contexts, une facture de régularisation is usually a bill sent later to correct the amount already paid, often after estimated monthly payments.

For example:

• you paid an estimated amount each month
• then the company checks the real total
• if there is a difference, they send une facture de régularisation

So here régularisation is not just a general abstract noun; it refers to a financial adjustment.

Because change is the conjugated form, while changer is the infinitive.

The subject is La facture de régularisation, which is singular, so the verb must be third person singular:

• je change
• tu changes
• il / elle / on change
• nous changeons
• vous changez
• ils / elles changent

So:

• La facture de régularisation change la mensualité.

is correct because la facture is singular.

French uses articles much more often than English.

Here:

• La facture de régularisation = the adjustment bill
• la mensualité = the monthly payment

In English, we sometimes drop articles more easily, especially in headlines or short notes, but French usually keeps them in a full sentence.

So French prefers:

• La facture change la mensualité.

rather than dropping the articles.

Not exactly.

Une mensualité usually means:

• a monthly payment
• an installment paid each month

It refers to the amount you pay every month, not necessarily the bill itself.

That is different from:

• une facture mensuelle = a monthly bill

So in this sentence, la mensualité is the regular monthly amount being paid, and the adjustment bill changes that amount.

Because mensualité is already a noun meaning monthly payment/installment.

French often has both:

• an adjective: mensuel / mensuelle = monthly
• a noun: mensualité = monthly installment/payment

So:

• une facture mensuelle = a monthly bill
• une mensualité = a monthly payment

They are related, but they are not used in the same way.

The subject is La facture de régularisation.

A useful trick is to ask: What is doing the action?

What changes the monthly payment?

• La facture de régularisation

So that whole noun phrase is the subject, and:

• change = the verb
• la mensualité = the direct object

Structure:

• La facture de régularisation → subject
• change → verb
• la mensualité → direct object

Not grammatically. It is a prepositional phrase built with de + noun, but it functions a bit like an adjective because it describes facture.

So although régularisation is a noun, the whole phrase de régularisation tells us what kind of bill it is.

English often uses a noun directly before another noun:

• adjustment bill

French often uses:

• facture de régularisation

So it is not an adjective, but it plays a descriptive role.

Yes, possibly, depending on context.

• change = changes
• modifie = modifies

Both can work, but change is more general and very natural here.

Modifie may sound a bit more formal or technical. In many administrative or billing contexts, both are understandable, but change is simple and common.

So:

• La facture de régularisation change la mensualité.
  is perfectly natural.

Because the sentence is probably referring to a specific monthly payment amount already known in the situation.

• la mensualité = the monthly payment
• une mensualité = a monthly payment / one monthly installment

If you say la, it sounds like there is one known payment amount being discussed, for example in a contract, utility account, or payment plan.

That is why la mensualité is the most natural choice here.

A helpful approximate pronunciation is:

ray-gyoo-lah-ree-zah-syon

More carefully in French sound terms:

• ré sounds roughly like ray
• gu in régu- gives a hard g sound
• the final -tion is pronounced like syon

The stress in French is not like English word stress; it tends to fall toward the end of the phrase rather than strongly on one syllable.

You can map it word by word, but the most natural English may not match perfectly.

Word by word:

• La = the
• facture = bill / invoice
• de régularisation = adjustment / settlement / regularization
• change = changes
• la mensualité = the monthly payment

But French and English package billing terms differently, so the best translation depends on context.

For learning purposes, it is useful to see both:

• literal structure: The adjustment bill changes the monthly payment
• natural meaning in context: the bill adjusting the account changes the monthly payment amount

Yes, facture is feminine, which is why it takes:

• la facture

You usually have to learn the gender with the noun. There is no completely reliable rule just from meaning.

In this sentence:

• la facture shows facture is feminine
• la mensualité shows mensualité is also feminine

A good habit is to memorize nouns with their article:

• la facture
• la mensualité
• la régularisation

That makes correct French much easier later.