Learn Hardcore French: Je me brosse les dents devant le miroir. - I brush my teeth in front of the mirror.

Because se brosser is a reflexive verb when you’re brushing a part of your own body. The reflexive pronoun (me, te, se, nous, vous, se) shows the action is done to the subject.

Je me brosse les dents = I brush my own teeth.
Je brosse les dents (no reflexive) = I brush teeth (someone’s teeth in general, not clearly mine).
Je brosse le chien = I brush the dog (non‑reflexive, different meaning).

Why is it les dents and not mes dents?

With body parts, French usually uses the definite article (le, la, les) when the possessor is clear from a reflexive pronoun or the context. The reflexive me already tells us the teeth are mine, so les dents is the natural choice.
You’d use a possessive only to avoid ambiguity or add emphasis:

Je me brosse les dents. (normal)
Je me brosse mes dents. (nonstandard/odd; double marking)
Je brosse les dents de mon fils. (someone else’s teeth)

Is Je brosse mes dents acceptable?

It’s grammatically possible, but it sounds unnatural in everyday French. Native speakers say Je me brosse les dents. Use the reflexive construction with the definite article.

Is Je me brosse mes dents ever correct?

No. That’s double marking (reflexive + possessive) and is considered incorrect or at least very clumsy. Say Je me brosse les dents.

Where do I put the negation?

Wrap ne … pas around the reflexive pronoun and the verb:

Je ne me brosse pas les dents devant le miroir.
In speech, ne often drops: Je me brosse pas les dents… (informal).

How do I ask a yes/no question with this sentence?

Three common ways:

Intonation (informal): Tu te brosses les dents devant le miroir ?
Est-ce que: Est-ce que tu te brosses les dents devant le miroir ?
Inversion (formal): Te brosses-tu les dents devant le miroir ?

How do I say it in the past (passé composé)?

Use être with the reflexive:

Je me suis brossé les dents devant le miroir.
Note there’s no extra -e agreement on brossé here (see next question).

Why no agreement in Je me suis brossé les dents if I’m a woman?

With pronominal verbs, the past participle agrees with the direct object if it comes before the verb. In se brosser les dents, the reflexive me is an indirect object (you brush the teeth to yourself). The direct object les dents comes after the verb, so no agreement:

A man or a woman says: Je me suis brossé les dents.
Compare: Elle s’est lavée (no object; se is direct → agreement), but Elle s’est lavé les mains (object after → no agreement).

How do I give a command (imperative)?

Affirmative: pronoun after the verb with a hyphen; te → toi
- Brosse-toi les dents !
- Brossons-nous les dents !
- Brossez-vous les dents !
Negative: pronoun before the verb
- Ne te brosse pas les dents !
- Ne nous brossons pas les dents !
- Ne vous brossez pas les dents !

Why devant le miroir and not dans le miroir?

devant le miroir = physically in front of the mirror (your location).
dans le miroir = in the mirror’s reflection; you use this with verbs like se regarder: Je me regarde dans le miroir.
So for brushing (physical position), devant is the right preposition.

Why le miroir and not un miroir?

Both are possible. Le miroir implies a specific, known mirror (typically the bathroom mirror). Un miroir means “a mirror” (not a particular one). Context usually favors le miroir for routines.

Can I say la glace instead of le miroir?

Yes, in everyday French you’ll hear la glace meaning “mirror,” especially in France: Je me regarde dans la glace. Note la glace can also mean ice or ice cream; context disambiguates.

What’s the difference between devant and avant?

devant = in front of (space): Je suis devant le miroir.
avant = before (time or order): Je me brosse les dents avant de dormir.
Don’t use avant for physical location.

Can I replace les dents with a pronoun?

Yes: les. Full clitic order gives: Je me les brosse.
That’s grammatically correct but sounds a bit stiff in isolation. In real speech/writing, people usually say les dents explicitly unless the context makes it crystal clear.

Is se laver les dents okay, or must it be se brosser les dents?

Both exist. Se brosser les dents is the standard, neutral way. Se laver les dents is also used (some regions prefer it), but learners are safest with se brosser les dents.

What’s the gender and number of dent?

Une dent (feminine singular), des/les dents (feminine plural).
Agreement example: Mes dents sont blanches.

How do I pronounce the sentence naturally?

Je me often reduces: [ʒə mə].
brosse: [bʁɔs].
les dents: [le dɑ̃]; the final -ts in dents is silent.
devant: [dəvɑ̃]; final -t silent, nasal vowel at the end.
le miroir: [lə miʁwaʁ].
In fast speech you may hear the schwa drop: J’me brosse…

What’s the present-tense conjugation of se brosser?

Je me brosse
Tu te brosses
Il/Elle/On se brosse
Nous nous brossons
Vous vous brossez
Ils/Elles se brossent

Where do adverbs go?

Common adverbs like souvent, toujours, déjà typically go after the conjugated verb (and pronoun) but before the object:

Je me brosse souvent les dents devant le miroir.
Passé composé:
Je me suis déjà brossé les dents.

Can I say au miroir?

Not with devant. Au is the contraction of à + le, but the correct preposition here is devant: devant le miroir. You can say face au miroir or en face du miroir to mean “facing the mirror.”

What’s the noun for “toothbrush,” and how would I add it?

It’s une brosse à dents.
Example: Je me brosse les dents devant le miroir avec une brosse à dents.