Learn Hardcore French: Dans son journal intime, Marie raconte son stage et ses premiers jours de vie d'adulte. - In her diary, Marie tells about her internship and her first days of adult life.

journal is a masculine noun (un journal) → you must use son, regardless of who owns it.
If the noun were feminine, you’d use sa:
- son journal (masculine)
- sa voiture (feminine)
- ses journaux / ses voitures (plural)

So:

Marie écrit dans son journal.
Paul écrit dans son journal.

Both use son because journal is masculine, even though Marie is feminine and Paul is masculine.

What exactly does journal intime mean? Is it just “journal” or “newspaper”?

French journal is ambiguous on its own:

un journal = a newspaper
un journal intime = a private diary, a personal journal

The adjective intime here means very personal, private.

So:

journal → could be “newspaper” or “journal” depending on context.
journal intime → clearly “diary” / “private journal,” not a newspaper.

Using intime makes it clear we are talking about a personal diary where she writes her thoughts and experiences.

Why do we say dans son journal intime? Could we use en or à instead?

Here dans is the usual preposition for “in(side)” a concrete thing like a book, a notebook, a room, etc.

dans son journal intime = in her diary (physically written inside it)

You cannot say:

✗ en son journal intime
✗ à son journal intime

Those are ungrammatical in this sense.

Other examples with dans:

Dans son cahier, il note ses devoirs. – In his notebook, he writes down his homework.
Dans ce livre, l’auteur décrit sa jeunesse. – In this book, the author describes his youth.

So dans + [physical container / medium] is the natural pattern here.

What’s the nuance of raconte in Marie raconte son stage… compared to dit or parle de?

The verb raconter means to tell / to relate / to narrate a story or series of events in some detail.

raconter quelque chose = to tell/narrate something
- raconter son stage – to tell the story of her internship
- raconter sa journée – to tell how her day went

Compare:

dire quelque chose – to say something (often shorter, not necessarily a story)
- Elle dit qu’elle est fatiguée. – She says she’s tired.
parler de quelque chose – to talk about something (more general)
- Elle parle de son stage. – She talks about her internship (not necessarily narrating it as a story).

Here, raconte suggests that in her diary, Marie is recounting/relating her experiences in a narrative way, not just mentioning them.

What does son stage mean here? Is stage a “stage” like in a theater?

No. Un stage in French is a training period, usually:

an internship (in a company, as part of studies), or
a practical training course / work placement.

It’s a classic false friend for English speakers:

un stage ≠ a stage (the raised platform in a theater)
un stage ≈ an internship, a training course

So son stage means her internship / training placement, not “her stage.”

Why is raconte in the present tense? Would a raconté also be possible?

raconte is present indicative:

Marie raconte son stage… = Marie is telling / tells about her internship…

In literary or narrative French, the present is very often used as a “present of narration” (like the historical present in English) to make the story feel more vivid and immediate, even if the events she describes are in the past.

You could also use the past:

Marie a raconté son stage… – Marie told (has told) about her internship…
Marie racontait son stage… – Marie was telling about her internship…

All are grammatically correct, but the simple present is common when summarizing what someone does in a text, book, or diary, almost like a book blurb:

Dans ce roman, l’auteur décrit sa jeunesse.
Dans son journal intime, Marie raconte son stage…

Why is it ses premiers jours and not son premiers jours?

Again, the possessive agrees with the noun it modifies:

jour (day) is masculine singular → son premier jour
jours (days) is masculine plural → ses premiers jours

So:

son premier jour de travail – his/her first day of work
ses premiers jours de travail – his/her first days of work

In the sentence:

ses agrees with jours (plural)
premiers also agrees with jours (masculine plural)

Hence: ses premiers jours.

The expression ses premiers jours de vie d’adulte feels long. How is this structure working?

Break it down:

ses – her (plural possessive, agreeing with jours)
premiers jours – first days
de vie d’adulte – of adult life

So literally: “her first days of adult life.”

Grammar:

jours de vie: “days of life” → de introduces a noun complement explaining what kind of days.
vie d’adulte: “adult life” → d’adulte characterizes vie (life), similar to an adjective.

French often uses de + noun or d’ + noun instead of a simple adjective to describe a type of life, day, job, etc.:

une vie d’étudiant – student life
une vie de famille – family life
les premiers jours de vie d’adulte – the first days of (one’s) adult life

You will also see slightly different but equivalent patterns:

ses premiers jours de vie adulte – with adulte used as an adjective
les premiers jours de sa vie d’adulte – “the first days of her adult life”

All are possible; the original is a compact way to avoid having sa twice (ses premiers jours de sa vie d’adulte sounds heavy).

Why is it d’adulte in the singular and not de la vie des adultes or d’adultes?

Here, adulte is not “a specific adult” or “adults” in general; it’s used almost like an adjective to describe a type of life:

vie d’adulte ≈ “adult life” as a state
similar to vie d’étudiant – student life, vie de retraité – retired life

It’s singular because it refers to the quality/state (being an adult), not the number of adults.

If you said:

vie des adultes – the life of adults (plural), more about the life that adults, as a group, lead.
vie d’adultes – life of adults, more literally focused on a group of adults.

Those would change the nuance. Vie d’adulte is the idiomatic way to say “adult life” as a phase of someone’s personal existence.

Why is there no article before vie in ses premiers jours de vie d’adulte (not de la vie d’adulte)?

When de + noun is used to describe the type of something in a general way, French often omits the article:

un moment de bonheur – a moment of happiness
un air de fête – a festive atmosphere
une vie d’aventure – a life of adventure

Similarly:

ses premiers jours de vie d’adulte – her first days of adult life (as a type of life)

If you say:

les premiers jours de la vie d’adulte – the first days of the adult life

this is also grammatically correct, but it feels more specific, heavier, and a bit less idiomatic in this context. The version without the article is lighter and sounds more like a general phase in life.

Could we change the word order, for example: Marie raconte, dans son journal intime, son stage…? Would the meaning change?

Yes, you can move the prepositional phrase dans son journal intime. All of these are grammatically correct:

Dans son journal intime, Marie raconte son stage…
Marie raconte, dans son journal intime, son stage…
Marie raconte son stage dans son journal intime.

The meaning is essentially the same: Marie tells these things in her diary.

Nuance:

Placing Dans son journal intime at the beginning (version 1) highlights the context/medium first – “In her diary, Marie…” (typical of written French summaries).
Placing it at the end (version 3) feels more neutral and closer to natural spoken order.
Version 2, with commas, sounds a bit more formal or written.

So the original choice is mostly stylistic, not grammatical.