Mes sœurs s’écrivent souvent l’une à l’autre pendant les vacances.

The s’ is the shortened form of se, a reflexive pronoun.

In this sentence, se écrire is being used in a reciprocal sense, not a truly reflexive one. That means the sisters are doing the action to each other:

• Mes sœurs s’écrivent = My sisters write to each other

So here, s’ means something like to each other, not to themselves.

Because écrire starts with a vowel sound, se becomes s’:

• se écrire → s’écrire

Good question. s’ already suggests a reciprocal action, so l’une à l’autre is not strictly required for basic meaning.

But l’une à l’autre adds clarity and emphasis:

• Mes sœurs s’écrivent = My sisters write to each other
• Mes sœurs s’écrivent l’une à l’autre = My sisters write to one another

It makes the mutual relationship more explicit. French often uses both together for precision or style.

L’une à l’autre literally means the one to the other, and in natural English it means:

• to each other
• to one another

Because sœurs is feminine plural, French uses the feminine form l’une.

Compare:

• masculine or mixed group: l’un à l’autre
• feminine group: l’une à l’autre

Because the subject is Mes sœurs, which is third person plural.

The present tense of écrire goes like this:

• j’écris
• tu écris
• il/elle écrit
• nous écrivons
• vous écrivez
• ils/elles écrivent

So:

• Mes sœurs écrivent → third person plural
• with the reciprocal pronoun: Mes sœurs s’écrivent

In French, écrire à quelqu’un means to write to someone.

So in this sentence, the idea is not just that the sisters are writing in general, but that they are writing to one another.

That is why s’écrire here means:

• to write to each other

You could think of it as coming from:

• écrire à sa sœur = to write to one’s sister

Because the indirect object is expressed through the pronoun se / s’.

With full nouns, you would say:

• Ma sœur écrit à mon autre sœur.

With reciprocal pronouns, French uses:

• Mes sœurs s’écrivent.

The à is not written separately because the pronoun already fills that role.

Then l’une à l’autre repeats the relationship more explicitly.

In French, short adverbs like souvent, toujours, déjà, bien, etc. often come after the conjugated verb.

So:

• Mes sœurs s’écrivent souvent...

This is a very normal placement.

In English, we often say:

• My sisters often write to each other

French usually prefers:

• subject + verb + adverb

Pendant means during.

So:

• pendant les vacances = during the holidays / during vacation

It tells you when the action happens.

French often uses pendant for an action happening within a period of time.

French usually uses vacances in the plural when talking about a holiday period or vacation.

So even when English might say vacation in the singular, French commonly says:

• les vacances = the holidays / vacation time

This is just the normal French expression.

Examples:

• Je pars en vacances. = I’m going on vacation.
• Pendant les vacances = during the holidays

In French, the possessive adjective mes is used for plural nouns, whether they are masculine or feminine.

So:

• mon frère = my brother
• ma sœur = my sister
• mes frères = my brothers
• mes sœurs = my sisters

The plural form is simply mes for both genders.

Sœurs can be tricky because of the œ sound.

A rough pronunciation is:

• sur but with rounded lips

IPA:

• sœurs = /sœʁ/

The œ sound is like the vowel in French cœur or heure (though exact pronunciation can vary by accent).

Also note:

• the final s in sœurs is normally silent

A careful pronunciation is approximately:

Mes sœurs s’écrivent souvent l’une à l’autre pendant les vacances.

IPA: /me sœʁ se.kʁiv suvɑ̃ lyn a lotʁ pɑ̃dɑ̃ le vakɑ̃s/

A few useful points:

• Mes sounds like may
• sœurs has the rounded vowel /œ/
• s’écrivent sounds roughly like say-kreev
• souvent ends with a nasal vowel
• l’une à l’autre has a smooth flow between words
• final consonants are often silent unless there is liaison

Yes, absolutely.

That sentence is still correct:

• Mes sœurs s’écrivent souvent pendant les vacances.

It already means:

• My sisters often write to each other during the holidays.

Adding l’une à l’autre just makes the reciprocal meaning more explicit and slightly more elegant or emphatic.

Formally, it uses a reflexive pronoun (se / s’), but the meaning here is reciprocal.

That distinction matters:

• reflexive: someone does something to themselves
• reciprocal: people do something to each other

Here, the sisters are not writing to themselves individually; they are writing to each other. So the meaning is reciprocal.