Je crois qu’il est déjà au bureau.

Because que becomes qu’ before a word starting with a vowel sound, like il. This is called elision.

• que il → qu’il

French does this to make pronunciation smoother. You will see this a lot:

• que elle → qu’elle
• que on → qu’on
• que il est → qu’il est

So Je crois qu’il... is the normal correct form.

Here, que means that and introduces a new clause:

• Je crois = I believe / I think
• qu’il est déjà au bureau = that he is already at the office

In English, that is often optional:

• I think (that) he is already at the office

In French, que is normally required here, so you usually cannot leave it out.

Crois is the 1st person singular form of the verb croire (to believe, often also to think).

The verb goes like this in the present tense:

• je crois = I believe / I think
• tu crois
• il/elle croit
• nous croyons
• vous croyez
• ils/elles croient

So Je crois simply means I believe or I think.

They are often similar, and in many contexts both can mean I think.

• Je crois qu’il est déjà au bureau.
• Je pense qu’il est déjà au bureau.

Both are possible.

A rough difference is:

• je crois often sounds a bit like I believe / I think it’s true
• je pense often sounds more like I think / in my opinion

But in everyday speech, there is a lot of overlap.

Est is the 3rd person singular present form of être (to be).

• il est = he is

Since the subject is il, the verb must match it:

• je suis
• tu es
• il est
• nous sommes
• vous êtes
• ils sont

So qu’il est déjà au bureau means that he is already at the office.

Grammatically, il can mean he or it depending on context.

In this sentence, it will usually mean he, because être au bureau strongly suggests a person being at work or at the office.

So most learners should understand it as:

• he is already at the office

But French itself does not tell you whether il is he or it without context.

Déjà is an adverb, and in this sentence it modifies the idea of is at the office.

French adverbs are often placed after the verb être:

• Il est déjà là. = He is already there.
• Il est déjà au bureau. = He is already at the office.

So il est déjà au bureau is the natural order.

If you put déjà somewhere else, the sentence may sound unusual or change the emphasis.

Yes. In many contexts, déjà means already, which is the meaning here.

But depending on context, it can also have shades like:

• before
• ever
• for a start / to begin with in spoken language

Examples:

• Tu es déjà allé en France ? = Have you ever been to France?
• Déjà, ce n’est pas vrai. = First of all, that’s not true.

In Je crois qu’il est déjà au bureau, the meaning is clearly already.

Because à + le contracts to au in French.

So:

• à + le = au
• à + les = aux

That means:

• au bureau = at the office
• literally from à le bureau

This kind of contraction is mandatory in standard French.

Because au bureau usually means at the office / at work, while dans le bureau means in the office / inside the office room.

So the difference is:

• Il est au bureau. = He is at the office / at work.
• Il est dans le bureau. = He is in the office room.

English often uses at the office, and French matches that with au bureau.

Because after an affirmative expression like je crois que, French normally uses the indicative, not the subjunctive.

So:

• Je crois qu’il est déjà au bureau. ✅

This is because the speaker presents it as something they believe to be true.

You are more likely to see the subjunctive after doubt, negation, or uncertainty, for example:

• Je ne crois pas qu’il soit au bureau.

So in your sentence, est is the expected form.

A careful pronunciation would be approximately:

zhuh krwah keel eh day-zhah oh byu-roh

A few useful points:

• Je sounds like zhuh
• crois sounds like krwah
• qu’il sounds like keel
• est sounds like eh
• déjà sounds like day-zhah
• au sounds like oh
• bureau sounds roughly like byu-roh

In natural speech, it flows together smoothly:

Je crois qu’il est déjà au bureau.

Normally, no. French usually keeps the subject pronoun.

So you say:

• Je crois qu’il est déjà au bureau.

Not:

• Crois qu’il est déjà au bureau. ❌

In very informal speech, native speakers may shorten things, but for learners, it is best to keep je. French is much less flexible than English about leaving out the subject.

It is understandable, but Il est déjà au bureau is more natural.

French usually places déjà before the place phrase here:

• Il est déjà au bureau. ✅ natural
• Il est au bureau déjà. possible, but less neutral

The second version can sound marked or more conversational, with extra emphasis on déjà. For a learner, the first version is the safest choice.