Le jaunissement change la couleur du feuillage.

Jaunissement is a masculine noun. It means yellowing as a process or result.

It comes from the verb jaunir (to turn yellow / to yellow).
So:

• jaunir = verb
• le jaunissement = the yellowing

French often uses nouns like this where English might use either a noun or a verb.

French usually needs an article before a noun, especially when talking about something in a general sense.

So Le jaunissement means yellowing in a general or specific sense, depending on context. Here it is talking about the phenomenon itself, so the definite article le is natural.

English often drops the article in this kind of sentence, but French usually does not.

Because it is a masculine noun in French: le jaunissement.

There is not always a logical reason a noun is masculine or feminine, so this usually has to be learned with the word. A useful clue is that many nouns ending in -ment are masculine, and jaunissement follows that pattern.

Change is the present tense form of changer for il / elle / on and also for any singular noun subject.

Here the subject is Le jaunissement, which is singular, so the verb must be singular too:

• Le jaunissement change
• Le vieillissement change
• Le froid change

So change here means changes.

La couleur uses the definite article because French often uses definite articles where English might say the, a, or sometimes no article at all, depending on context.

Here la couleur du feuillage means the color of the foliage in a general or known sense. It is talking about that characteristic of the foliage.

If you said une couleur, it would sound more like a color, which would change the meaning.

Here du is the contraction of de + le:

• de + le = du

So:

• la couleur du feuillage
• literally: the color of the foliage

In this sentence, du feuillage means of the foliage.
This du is not the partitive article here; it is the contracted form of de le.

Feuillage is a collective noun meaning foliage or leaf cover. It refers to the mass of leaves as a whole, not to individual leaves.

So:

• les feuilles = the leaves
• le feuillage = the foliage

Using feuillage sounds more general, botanical, or descriptive. It is often preferred when talking about plants, trees, or overall appearance.

It is grammatically singular: le feuillage.

Even though it refers to many leaves, it works like a collective noun, similar to how English uses foliage. That is why the sentence says du feuillage, not des feuillages.

Because standard French word order is:

subject + verb + object

Here:

• Le jaunissement = subject
• change = verb
• la couleur du feuillage = direct object

So the sentence follows the normal French pattern very closely.

Yes, that is possible.

• change = changes
• modifie = modifies

Both are correct, but change is simpler and more direct. Modifie can sound a bit more formal or technical.

A rough pronunciation is:

zhaw-nee-smã

More carefully:

• jau- sounds roughly like zho
• -nis- sounds like nee
• -sement / -ssement ends with a nasal sound, not a fully pronounced n

A more IPA-style version is:

/ʒo.nis.mɑ̃/

If pronunciation is difficult, focus especially on:

• the French j sound: /ʒ/
• the nasal ending -ment here: /mɑ̃/

Yes. Jaunissement can be used for any kind of yellowing, depending on context, for example:

• le jaunissement des feuilles = the yellowing of leaves
• le jaunissement du papier = the yellowing of paper
• le jaunissement de la peau = yellowing of the skin

So it is a general noun meaning yellowing, not a word limited only to plants.