Mon neveu est censé dormir, mais il écoute encore la conversation sur les fiançailles depuis le couloir.

Mon neveu means my nephew. French usually uses a possessive adjective like mon, ton, son, notre where English uses my, your, his/her, our.

So:

• mon neveu = my nephew
• le neveu = the nephew

You use le neveu only when you mean the nephew in a more general or already identified sense, not when saying whose nephew he is.

Être censé + infinitive means to be supposed to + verb or to be expected to + verb.

So:

• Il est censé dormir = He is supposed to be sleeping / He is supposed to sleep

In this sentence, it suggests that sleeping is what he should be doing, but in fact he is doing something else.

This structure is very common:

• Je suis censé partir à 8 heures. = I’m supposed to leave at 8.
• Tu es censé savoir ça. = You’re supposed to know that.

Because after est censé, French uses the infinitive.

So the pattern is:

• être censé + infinitive

Examples:

• Il est censé dormir.
• Nous sommes censés arriver demain.
• Elle est censée comprendre.

You do not say il est censé dort because dort is a conjugated form, and French needs the infinitive after this expression.

The accent in censé is part of the spelling of the word. It is the past participle/adjective form of censer in this expression.

So:

• censé = supposed
• not cense

The accent matters in written French and helps distinguish the correct form.

Also, censé agrees like an adjective in many contexts:

• Il est censé dormir.
• Elle est censée dormir.
• Ils sont censés dormir.
• Elles sont censées dormir.

French often expresses this more simply than English.

• Il est censé dormir literally looks like He is supposed to sleep
• but in context it can naturally mean He is supposed to be sleeping

French does not need a separate equivalent of English to be here. The infinitive dormir is enough.

If you want to emphasize the ongoing action, French could also say:

• Il est censé être en train de dormir.

But that is heavier, and the shorter Il est censé dormir is very natural.

Because écouter takes a direct object in French.

• écouter quelque chose / quelqu’un = to listen to something / someone

So:

• il écoute la conversation = he is listening to the conversation

This is different from English, which uses listen to.

Compare:

• J’écoute la radio. = I’m listening to the radio.
• Elle écoute son frère. = She’s listening to her brother.

By contrast, parler à, téléphoner à, etc. do use à, but écouter does not.

Here encore means still.

So:

• il écoute encore = he is still listening

That means the action is continuing.

Depending on context, encore can also mean again:

• Dis-le encore. = Say it again.

But in this sentence, still is the natural meaning because he continues to listen when he should be asleep.

French adverbs often come after the conjugated verb, especially short common adverbs like encore, bien, déjà, souvent.

So:

• il écoute encore la conversation

This is the normal word order.

English often places still before the main verb:

• he is still listening

But French structure is different.

You could think of it as:

• verb first: écoute
• then adverb: encore

Sur here means about/on the subject of.

So:

• une conversation sur les fiançailles = a conversation about the engagement

French often uses sur to indicate the topic of a discussion, talk, article, or debate.

Examples:

• un livre sur l’histoire de France = a book about French history
• une discussion sur la politique = a discussion about politics

You could also hear à propos de in some contexts, but sur is very natural here.

In French, fiançailles is normally used in the plural.

• les fiançailles = engagement / engagement festivities / betrothal

Even when English says the engagement in the singular, French usually says les fiançailles.

Examples:

• Ils ont annoncé leurs fiançailles. = They announced their engagement.
• On parle des fiançailles de Marie. = We’re talking about Marie’s engagement.

So the plural is normal and expected.

Here depuis le couloir means something like from the hallway.

It tells you the place from which he is listening.

So the idea is:

• he is not in the room
• he is listening from the hallway

This use of depuis is not the time meaning since. It is the place/source meaning from.

Compare:

• depuis le couloir = from the hallway
• depuis hier = since yesterday

If the sentence said dans le couloir, that would mean in the hallway.
Depuis le couloir emphasizes the point of origin or position from which he is listening.

Yes, but the nuance changes a little.

• dans le couloir = in the hallway
• depuis le couloir = from the hallway

Dans le couloir focuses on where he is located.
Depuis le couloir focuses more on the fact that the listening is happening from that position, as a kind of source point.

In many contexts both are understandable, but depuis gives a slightly more precise sense of from the hallway.

The comma separates the two contrasting parts of the sentence:

• Mon neveu est censé dormir
• mais il écoute encore la conversation...

Mais means but, so the comma helps show the contrast clearly, just as in English.

It is very natural punctuation here because the second clause goes against the expectation created by the first one: he is supposed to be asleep, but he is still listening.

Yes. The main verbs are in the present tense:

• est = is
• écoute = listens / is listening

French often uses the simple present where English may choose either:

• the simple present, or
• the present continuous

So:

• il écoute can mean he listens or he is listening, depending on context

Here, because it is describing what is happening right now, English naturally says he is listening.

A few words are especially useful to notice:

• neveu sounds roughly like nuh-vuh
• censé has a clear ay sound at the end
• fiançailles is pronounced roughly fee-ahn-sigh
• couloir sounds roughly koo-lwar

Also, French links words smoothly, so in natural speech:

• Mon neveu est censé dormir may sound quite connected, with est censé flowing together.

Even if the meaning is already known, recognizing these sound patterns can help you catch the sentence more easily when spoken.

Yes, est supposé dormir is possible and often understandable, but est censé dormir is usually the more idiomatic choice for is supposed to be sleeping in this kind of context.

In everyday French:

• être censé = to be supposed to
• être supposé can also be used, but sometimes sounds more literal or less natural depending on context

So for a learner, être censé + infinitive is a very useful pattern to remember.