Chaque fois que mon feutre ne fonctionne plus, j’efface l’ardoise et j’en prends un autre.

Yes. Chaque fois que means every time or each time that.

So:

• Chaque fois que mon feutre ne fonctionne plus...
  = Every time my marker stops working...

It introduces a repeated situation: whenever this happens, the speaker does the same thing.

A close English translation is:

• Every time my marker stops working, I erase the board and take another one.

Here, feutre means a felt-tip pen or marker.

In context, it is probably the kind of marker used to write on a board. So mon feutre is my marker.

French feutre can mean different things depending on context, but in a classroom or writing context, marker is the natural meaning.

Because feutre is a masculine noun in French.

So the possessive adjective is:

• mon for masculine singular nouns
• ma for feminine singular nouns
• mes for plural nouns

Examples:

• mon feutre = my marker
• ma gomme = my eraser
• mes stylos = my pens

Ne ... plus means no longer or not anymore.

So:

• mon feutre ne fonctionne plus
  literally = my marker no longer works naturally = my marker doesn’t work anymore

This is different from ne ... pas, which is the basic not.

Compare:

• Il ne fonctionne pas = It does not work
• Il ne fonctionne plus = It no longer works / It doesn’t work anymore

In this sentence, plus shows that the marker used to work, but now it has stopped working.

Because plus already completes the negative structure with ne.

In French, different negative expressions use ne plus another word:

• ne ... pas = not
• ne ... plus = no longer / not anymore
• ne ... jamais = never
• ne ... rien = nothing

So you do not say:

• ne fonctionne pas plus for this meaning

You say:

• ne fonctionne plus

Yes. In French, fonctionner is often used for things that work / function properly.

So:

• Mon feutre fonctionne = My marker works
• Mon feutre ne fonctionne plus = My marker doesn’t work anymore

This is perfectly natural French.

That said, depending on context, a French speaker might also say something like:

• Mon feutre n’écrit plus = My marker doesn’t write anymore

That focuses more specifically on the fact that it no longer writes.

It means I erase the board or I wipe the slate/board clean.

Breakdown:

• j’efface = I erase
• l’ardoise = the slate / board

The verb effacer means to erase, to wipe off, or to rub out, depending on context.

Literally, ardoise means slate. But in context, it can refer to a small slate board, a writing board, or sometimes a classroom-type board.

So j’efface l’ardoise could be understood as:

• I erase the slate
• I wipe the board clean

The best translation depends on the situation the learner has already been shown.

Because ardoise starts with a vowel sound, and in French la becomes l’ before a vowel or mute h.

So:

• la ardoise → incorrect
• l’ardoise → correct

This is called elision.

The same thing happens in:

• je efface → j’efface
• je en prends → j’en prends

It means I take another one.

Breakdown:

• j’ = I
• en = of it / one of them / some
• prends = take
• un autre = another one

So the whole idea is:

• I erase the board and take another one
• meaning: another marker

En is used to replace a noun introduced by de, or to avoid repeating a thing already understood from context.

Here, en stands for something like one of those / one of them, referring back to feutre.

So instead of repeating:

• je prends un autre feutre

the sentence says:

• j’en prends un autre

This is very natural French.

You can think of it as:

• I take another one
• where one refers to the marker already mentioned

Yes, absolutely.

• j’en prends un autre = I take another one
• je prends un autre feutre = I take another marker

The version with en is smoother and avoids repetition, which is very common in French.

Because autre usually needs a determiner here.

So French says:

• un autre = another one / another
• une autre = another one / another, feminine
• d’autres = others / other ones

Since feutre is masculine singular, the sentence uses:

• un autre

Examples:

• Je veux un autre stylo. = I want another pen.
• J’en prends un autre. = I’m taking another one.

Because the sentence describes a habitual action: something the speaker does regularly whenever a certain situation happens.

French often uses the present tense for habits and general truths, just like English does.

So:

• Chaque fois que mon feutre ne fonctionne plus, j’efface l’ardoise et j’en prends un autre.

means something like:

• Whenever my marker stops working, I erase the board and take another one.

It is not necessarily happening right now; it is a repeated pattern.

No inversion is needed here. Chaque fois que simply introduces a subordinate clause, and French keeps normal subject-verb order:

• mon feutre ne fonctionne plus

Then the main clause follows:

• j’efface l’ardoise et j’en prends un autre

This is similar to English:

• Every time my marker stops working, I erase the board and take another one.

Because the speaker is doing two linked actions in sequence:

1. j’efface l’ardoise = I erase the board
2. j’en prends un autre = I take another one

So et simply means and.

It connects the two things the speaker habitually does when the marker stops working.

Yes, it is natural and grammatically correct.

A native speaker would understand it easily. Depending on context, they might also say slightly different versions, for example:

• Chaque fois que mon feutre n’écrit plus, j’efface l’ardoise et j’en prends un autre.
• Quand mon feutre ne marche plus, j’efface l’ardoise et j’en prends un autre.

But the original sentence is perfectly good French.

Yes, en is pronounced, but not as a fully separate English-style word. It flows together with the verb.

Very roughly:

• j’en prends un autre

sounds something like:

• zhahn prahn uh-nohtr

A few useful points:

• j’ is linked directly to en
• prends is pronounced like pran
• the s in prends is normally silent
• un autre links smoothly in speech

You do not pronounce each word in a stiff, separate way; French connects them naturally.