Paul commence à s’étouffer pendant l’exercice.

In French, commencer à + infinitive means to begin to do something.

So:

• commence à s’étouffer = begins to choke
• literally: begins to choke himself/herself, though that literal reflexive idea is not how you normally translate it

This is just the standard pattern with commencer when it is followed by another verb.

Examples:

• Il commence à courir. = He begins to run.
• Nous commençons à comprendre. = We’re beginning to understand.

S’étouffer is the pronominal/reflexive form of the verb.

• étouffer can mean to suffocate, to smother, or to choke
• s’étouffer means to choke, to be choking, or sometimes to suffocate

In this sentence, Paul commence à s’étouffer means that Paul himself is the one experiencing the choking.

Compare:

• Il étouffe le feu. = He smothers the fire.
• Il s’étouffe. = He is choking.

So the se / s’ changes the meaning and is important here.

Here, s’étouffer most naturally means to choke or to start choking.

Depending on context, it can also suggest:

• struggling to breathe
• choking on something
• beginning to suffocate

In everyday usage, it often refers to a physical choking episode, especially if someone can’t breathe properly.

So in this sentence, the most natural interpretation is that Paul starts choking during the exercise.

This is called elision.

French usually drops the vowel in short words like se before another word that begins with a vowel or silent h.

So:

• se étouffer becomes s’étouffer

You see the same thing in many other cases:

• je aime → j’aime
• le exercice → l’exercice
• ne a → n’a

It helps French sound smoother.

Commence is the present tense of commencer.

Here it is:

• je commence
• tu commences
• il / elle / on commence
• nous commençons
• vous commencez
• ils / elles commencent

So Paul commence à s’étouffer is in the present tense and means something like:

• Paul begins to choke
• Paul is starting to choke

L’ is the definite article, meaning the.

So pendant l’exercice means during the exercise.

French often uses the definite article in places where English might also use the, especially when referring to a specific event or activity already understood from context.

If you said pendant un exercice, that would mean during an exercise or during one exercise, which sounds less specific.

So:

• pendant l’exercice = during the exercise
• pendant un exercice = during an exercise

Usually, yes, but it depends on context.

Exercice can mean:

• physical exercise
• a practice drill
• an exercise or task

So pendant l’exercice could mean:

• during the workout
• during the exercise session
• during the drill/practice activity

If the broader context is sports, school PE, military training, or a fitness activity, it would likely mean some kind of physical exercise.

Pendant means during or for, depending on the sentence.

In this sentence, it means during:

• pendant l’exercice = during the exercise

It places the action in time.

Examples:

• Pendant le cours, il dort. = He sleeps during class.
• Pendant deux heures, elle a travaillé. = She worked for two hours.

Here, it tells you when Paul starts choking.

Sometimes you may hear étouffer used without se, especially in certain contexts, but s’étouffer is the more natural and standard choice when talking about a person choking.

Compare the feel of the two:

• Paul commence à s’étouffer. = Paul begins choking.
• Paul commence à étouffer. = Paul begins to suffocate / Paul starts choking.

The version with se is more idiomatic for a person who is choking.

Yes.

That would mean:

• Paul is in the process of choking
• Paul is choking right now

The difference is:

• Paul commence à s’étouffer = Paul is starting to choke
• Paul est en train de s’étouffer = Paul is choking right now / in the middle of it

So commence à focuses on the beginning of the action, while est en train de focuses on the action in progress.

Yes, absolutely.

Both are correct:

• Paul commence à s’étouffer pendant l’exercice.
• Pendant l’exercice, Paul commence à s’étouffer.

The meaning is basically the same. Moving pendant l’exercice to the front just puts more emphasis on the time frame.

This kind of movement is very common in French.

A natural pronunciation is roughly:

Paul commence à sétouffer pendant l’exercice

A few things to notice:

• s’étouffer is pronounced smoothly because of the elision
• l’exercice also links smoothly because of the apostrophe
• commence à is usually said very fluidly in normal speech

A rough English-style approximation could be:

Pol ko-mons ah say-too-fay pon-don ler-zehr-sees

That is only approximate, but it can help you hear the flow of the sentence.