Depuis qu'ils sont séparés, ils parlent surtout de leurs enfants par téléphone.

In French, depuis que + present tense is the normal way to express an action or state that started in the past and still continues now.

• Depuis qu’ils sont séparés literally: Since they are separated
  Natural English meaning: Since they (have been) separated / Ever since they split up.

So French uses the present where English often uses “have been” or “have done”:

• Ils habitent ici depuis 2010.
  → They have lived / have been living here since 2010.

• Depuis qu’ils sont séparés, ils parlent…
  → Since they separated, they (have) mainly been talking…

Using sont séparés focuses on the current state that began in the past and still holds true now.

All three are correct, but the nuance changes slightly:

1. Depuis qu’ils sont séparés

   • Focus on the ongoing state: they are now separated, and this state has been true since a certain point.
   • Very natural if you think of “they are separated” as a situation that continues.

2. Depuis qu’ils se sont séparés

   • Focus on the event of separating: the moment when they split up.
   • Literally: Since they split up (did the action of separating themselves)…
   • Slightly more “event-based” than “sont séparés,” which is more “state-based.”

3. Depuis leur séparation

   • Uses a noun: “their separation.”
   • Slightly more formal/neutral; works very well in written or more formal spoken French.
   • Literally: Since their separation, they mainly talk…

In everyday speech, depuis qu’ils sont séparés and depuis qu’ils se sont séparés are both common.
Depuis qu’ils sont séparés underlines the current situation; se sont séparés underlines the moment they split.

Here, sont séparés is best understood as être + adjective, not as a real passive of a verb.

• séparé originally comes from the past participle of séparer, but in this sentence it functions as an adjective meaning “separated” (maritally, emotionally, etc.).
• It agrees in gender and number with ils:
  • ils sont séparés → masculine plural → séparés
  • elles sont séparées → feminine plural → séparées
  • il est séparé, elle est séparée

If you wanted a clearly passive structure, you’d usually specify an agent:

• Ils sont séparés par la guerre. = They are separated by the war. (real passive)

In the original sentence, it just describes their marital/relationship status, so think of it as “they are separated (from each other).”

Because in French:

• parler de + noun = to talk about something/someone
• parler à + person = to talk to someone

So:

• Ils parlent surtout de leurs enfants.
  → They mainly talk about their children.

• Ils parlent surtout à leurs enfants.
  → They mainly talk to their children.

The sentence says they mostly talk about their children when they’re on the phone, not that they mostly talk to their children.

Two separate points:

1. leur / leurs (singular vs plural)
   • leur (no s) is used before a singular noun: leur enfant = their child
   • leurs (with s) is used before a plural noun: leurs enfants = their children

Because we’re talking about children (plural), French needs leurs.

2. leur(s) vs son / sa / ses
   • son, sa, ses refer to one owner (he, she, it).
     
     • ses enfants = his or her children.
   • leur, leurs refer to multiple owners (they).
     
     • leurs enfants = their (belonging to “they”) children.

Our subject is ils (they), so the children belong to both of them → leurs enfants.

surtout means roughly “above all / mainly / especially”.

In ils parlent surtout de leurs enfants, it modifies the verb phrase:

• It tells us what they mainly talk about:
  Their conversations are mostly about their children.

So a natural translation is:

• Since they separated, they mainly talk about their children on the phone.

It does not mean that they “mainly talk by phone” (as opposed to in person). That nuance would be expressed differently (see the next questions).

You can move surtout, but you must be careful, because you change what it seems to qualify.

1. Ils parlent surtout de leurs enfants par téléphone.
   Usual reading:

   • “They mainly talk about their children (and they do so by phone).”

2. Ils parlent de leurs enfants surtout par téléphone.
   Possible reading:

   • “They talk about their children, mainly by phone (rather than face-to-face).”

In (2), surtout is closer to par téléphone, so it sounds more like it is qualifying the means of communication.

Native speakers can understand both, but your chosen word order subtly guides what sounds like the main focus:

• surtout de leurs enfants → focus on what they mostly talk about.
• surtout par téléphone → focus on how they mostly talk (by phone).

Both are correct but have different emphases:

• par téléphone

  • Literally: by telephone, by phone.
  • Emphasizes the means/method of communication.
  • Very similar to English “by phone,” “over the phone.”

• au téléphone

  • Literally: at/on the telephone.
  • Often used for being on the line / on a call at a given moment.
  • E.g. Je suis au téléphone = I’m on the phone.

In your sentence:

• Ils parlent surtout de leurs enfants par téléphone.
  Stresses that the phone is the medium for these discussions.

You could say au téléphone here and it would still be understandable, but par téléphone is a bit more idiomatic to talk about a general means of communication.

No, not in that way. Depuis and depuis que are used differently:

• depuis + noun / date / point in time

  • Depuis leur séparation, ils parlent…
  • Depuis 2018, ils parlent…

• depuis que + clause (subject + verb)

  • Depuis qu’ils sont séparés, ils parlent…
  • Depuis qu’ils ont déménagé, ils parlent…

So you cannot say “Depuis ils sont séparés…”
You must either add:

• a noun: Depuis leur séparation, …
• or que and a full clause: Depuis qu’ils sont séparés, …

French doesn’t use a special progressive or perfect progressive form as systematically as English.

Where English often says:

• They *have been talking mainly about their children since they separated.*

French commonly uses the simple present with depuis (que):

• Depuis qu’ils sont séparés, ils parlent surtout de leurs enfants par téléphone.

This French present here covers the meaning of:

• “they have been talking”
• “they keep talking”
• “they generally talk”

So: present tense + depuis (que) often corresponds to English “have/has been + -ing”.

Yes, a few little things that learners often wonder about:

• Depuis → /də.pɥi/

  • The final s is silent.

• qu’ils → /kil/

  • There is no liaison sound here; it’s just /kil/.
  • Spelled with qu’ because ils starts with a vowel.

• sont séparés → /sɔ̃ se.pa.ʁe/

  • The t in sont is silent; no liaison before séparés.
  • séparés has the stress on the last syllable: se-pa-ré.

• parlent → /paʁl/

  • The -ent is silent; it isn’t pronounced differently from parle.

• leurs enfants → /lœʁz‿ɑ̃.fɑ̃/

  • Here there is a liaison:
    • leurs ends in a consonant sound /ʁ/,
    • enfants begins with a vowel /ɑ̃/,
    • so you get /lœʁz‿ɑ̃.fɑ̃/ (a little /z/ sound between them).

• téléphone → /te.le.fɔn/

  • Final -e is mute in connected speech, but the -on- is nasal /ɔ̃/.

Practising these liaisons and silent endings will make your pronunciation much more natural.