Learn Hardcore French: Nous voulons protéger la planète ensemble.

So you conjugate vouloir for the subject, and keep protéger in the infinitive. You never say nous voulons protégeons; that would be incorrect.

Why is there no preposition like à or de before protéger?

Some French verbs need a preposition before another verb (e.g. commencer à faire, essayer de faire), but vouloir does not.

Correct patterns:

vouloir + infinitive → Nous voulons protéger la planète.
essayer de + infinitive → Nous essayons de protéger la planète.
commencer à + infinitive → Nous commençons à protéger la planète.

So you say vouloir faire, vouloir protéger, etc., with no à or de in between.

Why is it la planète and not just planète without an article?

In French, a noun almost always needs an article (or a determiner). You can’t usually leave it “bare” like in English.

English: We want to protect planet Earth.
French: Nous voulons protéger la planète. (la is required)

Planète is a feminine noun, so it takes la in the singular: la planète. Using planète alone would sound ungrammatical in standard French in this kind of sentence.

Could we say notre planète instead of la planète? What’s the nuance?

Yes, you can say notre planète (our planet):

Nous voulons protéger notre planète.

Nuance:

la planète = the planet in general, more neutral or universal.
notre planète = emphasizes that it’s our planet, more personal and inclusive.

Both are correct; it’s mostly a stylistic choice.

Why is planète feminine? Is there a rule?

Planète is grammatically feminine simply by convention: la planète, une planète, cette planète.

There are some patterns (e.g. many nouns ending in -ette, -té, -tion are feminine), and planète fits the -ète / -ette pattern. But in practice, you just have to learn the gender of each noun with its article:

la planète (feminine)
le soleil (masculine)
la Terre (feminine, when meaning the planet Earth)

Could we say la Terre instead of la planète?

Yes, if you specifically mean planet Earth, you can say:

Nous voulons protéger la Terre.

Nuance:

la planète = the planet in a general, somewhat abstract way.
la Terre = Earth specifically, often used in environmental contexts to personify or specify our planet.

Both are common; choice depends on whether you want a more general or more specific reference.

Why is ensemble at the end? Can it go in other positions?

Ensemble is an adverb meaning together, and it’s very natural at the end of the sentence:

Nous voulons protéger la planète ensemble.

Other possibilities:

Ensemble, nous voulons protéger la planète. (quite natural, a bit more emphatic: Together, we want to protect the planet.)

This one is grammatically possible but feels heavier or more formal and is less common in everyday speech:

Nous voulons ensemble protéger la planète.

The neutral, most natural version for spoken French is exactly the one you have, with ensemble at the end.

How would you say “We don’t want to protect the planet together”?

You negate vouloir with ne … pas around the conjugated verb:

Nous ne voulons pas protéger la planète ensemble.

Structure:

Nous (subject)
ne … pas around voulons (the conjugated verb)
protéger (infinitive)
la planète (object)
ensemble (adverb)

In spoken French, people often drop ne and say:

Nous voulons pas protéger la planète ensemble. (common in speech, but not standard writing)

What’s the difference between nous voulons, on veut, and nous voudrions?

They all relate to we want, but differ in register and politeness:

Nous voulons protéger la planète ensemble.
Neutral, standard, slightly formal/written.
On veut protéger la planète ensemble.
Very common in spoken French; on is often used instead of nous in everyday conversation. Same meaning, more informal tone.
Nous voudrions protéger la planète ensemble.
Conditional form (voudrions) → sounds more polite or more tentative: We would like to protect the planet together. Often used when being diplomatic or making a polite proposal.

How would you say “We want to protect it together,” referring to la planète?

You replace la planète with la as a direct object pronoun and place it before the infinitive:

Nous voulons la protéger ensemble. = We want to protect it together.

Word order:

Subject: Nous
Conjugated verb: voulons
Object pronoun: la (it = the planet)
Infinitive: protéger
Adverb: ensemble

You cannot say Nous la voulons protéger ensemble in this case; with vouloir + infinitive, the object pronoun goes before the infinitive.

What tense is voulons here, and can it refer to the future?

Voulons is present tense (présent de l’indicatif).

In French, using vouloir in the present can express:

a present desire: Right now, we want to protect the planet together.
a more general intention, often about the present and future: We (as a group/organization) want to protect the planet together (in general, from now on).

If you want to talk about a concrete future action, you might also say:

Nous protégerons la planète ensemble. = We will protect the planet together. (future, more like a promise or prediction)

So nous voulons protéger la planète ensemble focuses on intention/will, not on a specific time schedule.

Can you drop nous and just say Voulons protéger la planète ensemble?

Not as a normal statement. In French, you normally need the subject pronoun:

Nous voulons protéger la planète ensemble. ✔️

If you start with Voulons protéger…, it sounds like an imperative (a command or suggestion), a bit like:

Voulons protéger la planète ensemble ! = Let’s want to protect the planet together! (and even then, it’s awkward and rarely said)

For a natural “Let’s protect the planet together,” you’d say:

Protégeons la planète ensemble. (imperative of protéger)