Learn Hardcore French: Dans le groupe, chacun imagine un futur différent, mais tous veulent être heureux. - In the group, everyone imagines a different future, but everyone wants to be happy.

Chacun is a singular indefinite pronoun meaning “each (person)” or “everyone (individually)”.
Grammatically it is always singular, so it must take a singular verb:

Chacun imagine — Each (person) imagines
❌ Chacun imaginent — ungrammatical

Even if you know there are many people in the group, French treats chacun as one person at a time for grammar purposes.

What is the difference between chacun and chaque?

Chaque is an adjective: it must be followed by a noun.
- Chaque personne imagine un futur différent.
  → Each person imagines a different future.
Chacun is a pronoun: it stands alone, it does not need a noun after it.
- Dans le groupe, chacun imagine un futur différent.
  → In the group, each (one) imagines a different future.

So you can think:

chaque + noun → each + noun
chacun → each one / everyone (individually)

What does tous mean here, and how is it different from chacun?

In this sentence:

chacun imagine un futur différent
→ focuses on individuals separately: each person imagines their own different future.
mais tous veulent être heureux
→ tous means “all (of them)” / “everyone (as a group)”, emphasizing what they all have in common.

So:

chacun = each person individually
tous = all of them together

Both refer to the same people, but from different angles:
first their differences, then their shared desire.

Could we say tout le monde veut être heureux instead of tous veulent être heureux?

Yes:

Mais tout le monde veut être heureux.
→ But everybody wants to be happy.

Differences in nuance and grammar:

tous here stands for a pronoun (implied ils):
- Tous veulent être heureux. (short for Ils veulent tous être heureux.)
  It sounds a bit more compact and slightly more formal/written.
tout le monde is itself a set phrase meaning “everybody” (literally all the world).
It is grammatically singular:
- Tout le monde veut (not veulent)

Both are idiomatic; the original sentence just chooses tous for stylistic variety (since chacun was already used before).

Why is it tous veulent and not tous veut, since tout le monde is singular?

Because tous and tout le monde don’t work the same way:

tout le monde → grammatically singular
- Tout le monde veut être heureux.
tous → refers to a plural subject (they all), so the verb must be plural
- Tous veulent être heureux.
  (Think: Ils veulent tous être heureux.)

So:

tous + plural verb
tout le monde + singular verb

Why is it un futur différent and not le futur différent?

Using un here emphasizes “a (personal) future”, not “the future” in general.

Chacun imagine un futur différent
→ Each person imagines a different future (for themselves).
The indefinite article un signals that each person’s future is one possible future among many, and each one is not the same as the others.

If you said:

Chacun imagine le futur.
This would sound odd or vague; it would suggest they’re all imagining “the” future in some general sense, not different individual futures.

What’s the difference between futur and avenir? Could we say un avenir différent instead?

Both futur and avenir can mean “future”, but they’re not always interchangeable:

l’avenir
- Common for personal life, plans, fate.
- Very natural in:
  - Chacun imagine un avenir différent.
le futur
- Also a grammatical term for the future tense (le futur simple, etc.).
- As a noun about time/life, it can sound a bit more abstract or formal than avenir, but it’s still correct.

In this sentence, un futur différent is fine and idiomatic, but many speakers might prefer:

Chacun imagine un avenir différent.

So yes, un avenir différent is perfectly correct, and in everyday speech, probably more frequent.

Why is heureux masculine plural? What if the group is all women?

Adjectives in French agree in gender and number with the noun or pronoun they describe.

Here, tous refers to people in the group, represented by an implied ils (they).
By default:

If the group is mixed (men + women) → use masculine plural:
- Ils sont heureux.
- Tous veulent être heureux.
If the group is only women, you’d use feminine plural:
- Toutes veulent être heureuses.
  → All (of them) want to be happy.
  Here both toutes and heureuses become feminine plural.

So the original heureux implies either a mixed group or that the masculine generic is being used.

Can tous be pronounced differently? I’ve heard both [tu] and [tus].

Yes, tous has two common pronunciations, depending on how it’s used.

As a pronoun before a verb (like in this sentence):
- Tous veulent être heureux.
  Pronounced [tu] (no s sound).
As a pronoun at the end of a clause, or for emphasis:
- Ils sont tous là. → usually [tus]
- Je les ai vus, tous. → [tus]

In tous veulent, the s is normally silent: [tu vœl].
There is no liaison here because the next word veulent starts with a consonant.

Could we say Ils veulent tous être heureux instead of tous veulent être heureux?

Yes:

Tous veulent être heureux.
Ils veulent tous être heureux.

Both are correct and very close in meaning: They all want to be happy.

Nuance:

Tous veulent être heureux.
→ Slightly more formal or written; starts with tous as the subject pronoun.
Ils veulent tous être heureux.
→ Very natural in speech; the subject ils is explicit, and tous emphasizes that all of them (not just some) want to be happy.

In everyday conversation, Ils veulent tous être heureux is probably more common, but the original sentence’s structure is perfectly standard.