L’enceinte fonctionne bien, mais mes écouteurs ne marchent plus depuis hier.

Because la becomes l’ before a vowel sound. Enceinte starts with e, so French contracts the article:

• la voiture
• l’enceinte

This happens with le and la before vowels or mute h.

Here, enceinte means speaker or loudspeaker.

This word can confuse learners because enceinte can also mean pregnant, but that is usually an adjective describing a person, as in Elle est enceinte.

In this sentence, l’enceinte fonctionne bien clearly means the speaker is working well.

Both verbs can mean to work for devices.

• fonctionner = to function / to operate
• marcher = to work, in a very common everyday sense

So both are natural here:

• L’enceinte fonctionne bien
• Mes écouteurs marchent

Using two different verbs in the same sentence also avoids repetition. A native speaker might just as well say:

• L’enceinte marche bien
• Mes écouteurs ne fonctionnent plus

All of these sound normal.

Écouteurs is plural because headphones/earphones usually come as a pair.

• un écouteur = one earbud / one earpiece
• des écouteurs = earphones / earbuds

So mes écouteurs means my earphones / my earbuds.

If you wanted to talk about a single one, you could say mon écouteur.

Because the subject is mes écouteurs, which is plural.

French verbs agree with their subject:

• l’enceinte fonctionne → singular subject, singular verb
• mes écouteurs marchent → plural subject, plural verb

The -ent ending marks third person plural, although in pronunciation it is usually silent.

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

So:

• mes écouteurs ne marchent plus = my earphones don’t work anymore / my earphones no longer work

This is a very common negative structure in French.

In everyday spoken French, people often drop ne and say:

• Mes écouteurs marchent plus

But in standard written French, you should keep both parts: ne ... plus.

This is one of the most important differences from English.

French often uses the present tense with depuis when something started in the past and is still true now.

So:

• Mes écouteurs ne marchent plus depuis hier

literally looks like My earphones no longer work since yesterday, but the natural English meaning is:

• My earphones haven’t been working since yesterday
• My earphones haven’t worked since yesterday

French does not need a present perfect here. The present tense is normal because the situation began yesterday and continues now.

Here, depuis means since.

It marks the starting point of an action or state that continues up to the present.

• depuis hier = since yesterday
• depuis lundi = since Monday
• depuis deux heures = for two hours

A useful idea:

• depuis + starting point → since
• depuis + duration → often for

Bien is an adverb meaning well.

So:

• fonctionne = works / functions
• fonctionne bien = works well

It tells us that the speaker is not just operating, but operating properly.

Without bien, the sentence would simply say the speaker works. With bien, it emphasizes that the speaker is working fine.

Because the sentence is talking about my headphones, not headphones in general.

• mes écouteurs = my headphones
• les écouteurs = the headphones

French uses possessive adjectives like mon, ma, mes to show ownership, just as English uses my.

In careful spoken French, it would be very close to the written form.

In casual speech, many speakers drop ne, so you may hear:

• L’enceinte fonctionne bien, mais mes écouteurs marchent plus depuis hier.

That is very common in conversation, but for writing and for standard grammar, keep:

• L’enceinte fonctionne bien, mais mes écouteurs ne marchent plus depuis hier.