Quand Paul parle trop vite, il oublie parfois une syllabe.

Quand means when and introduces a time clause.

So Quand Paul parle trop vite means When Paul speaks too fast.

In French, a clause with quand can come before or after the main clause:

• Quand Paul parle trop vite, il oublie parfois une syllabe.
• Il oublie parfois une syllabe quand Paul parle trop vite.

Both are correct.

Because the subject is Paul, which is third person singular.
The verb parler in the present tense changes like this:

• je parle
• tu parles
• il/elle/on parle
• nous parlons
• vous parlez
• ils/elles parlent

Since Paul = he, you use parle.

Yes, Paul is already the subject of the first verb: Paul parle.

But the sentence has two verbs:

1. Paul parle
2. il oublie

French needs a subject for each finite verb, just like English:

• When Paul speaks too fast, he sometimes forgets a syllable.

So il refers back to Paul and is required for oublie.

French often uses the present tense for things that are generally true, habitual, or repeated.

Here, the sentence describes a repeated situation:

• When Paul speaks too fast, he sometimes forgets a syllable.

It is not talking about just one specific moment, so the present tense is natural in both clauses.

Trop means too much / too, and vite means quickly / fast.

Together, trop vite means too fast.

Examples:

• Tu marches trop vite. = You walk too fast.
• Elle parle trop vite. = She speaks too fast.

Both can mean quickly, but vite is much more common in everyday speech and often sounds more natural.

So:

• parler vite = very common
• parler rapidement = correct, but a bit more formal or less conversational in many contexts

In this sentence, trop vite is the most natural choice.

Parfois means sometimes. In French, adverbs like this are often placed near the verb, but their exact position can vary.

Here:

• il oublie parfois une syllabe

This is a very natural word order.

You may also see:

• Parfois, il oublie une syllabe.
• Il oublie une syllabe parfois.

But il oublie parfois une syllabe is smooth and standard.

In French, singular countable nouns usually need an article.

So you normally say:

• une syllabe = a syllable
• la syllabe = the syllable

Unlike English, French generally does not drop the article in this kind of sentence.

So oublier une syllabe is the normal structure.

Une syllabe suggests that when this happens, he forgets a syllable—one syllable at a time, or at least that is the typical idea.

If you said des syllabes, it would suggest some syllables / several syllables, which changes the meaning.

So:

• il oublie parfois une syllabe = he sometimes forgets a syllable
• il oublie parfois des syllabes = he sometimes forgets syllables / some syllables

Both are possible French, but they do not mean exactly the same thing.

Quand is pronounced roughly like kahn with a nasal vowel.
The d is silent.

Important points:

• it is not pronounced like English kwand
• the an sound is nasal
• the final d is not pronounced

A simple learner-friendly approximation is kahn.

This part can be tricky because Paul and parle look similar.

A rough guide:

• Paul sounds like pole
• parle sounds roughly like parl (one syllable)

So:

• Paul parle ≈ pole parl

The two words are distinct:

• Paul has the o sound
• parle has the a sound

There is no major required liaison that beginners especially need to worry about here.

A few pronunciation notes:

• Quand Paul: normally no pronounced final d in quand
• trop vite: no liaison
• parfois une: you may hear smooth linking in natural speech, but nothing unusual for a beginner to memorize first

The main challenge is more the individual sounds than liaison.

The comma separates the introductory when-clause from the main clause:

• Quand Paul parle trop vite, il oublie parfois une syllabe.

This works much like English:

• When Paul speaks too fast, he sometimes forgets a syllable.

If the main clause came first, the comma is often omitted:

• Il oublie parfois une syllabe quand Paul parle trop vite.

Yes. In a sentence like this, quand can express a repeated situation, so in English the idea is close to when or whenever.

So the sentence can feel like:

• When Paul speaks too fast, he sometimes forgets a syllable.
• Whenever Paul speaks too fast, he sometimes forgets a syllable.

The exact translation depends on context, but the French is perfectly natural for a habitual meaning.

Yes, but the meaning becomes a bit more explicit.

• il oublie parfois une syllabe = he sometimes forgets a syllable
• il oublie parfois de prononcer une syllabe = he sometimes forgets to pronounce a syllable

The second version spells out exactly what kind of forgetting is happening.
The original is shorter and very natural, especially when the context is speech.

Yes, it is very natural.

It sounds like standard, everyday French:

• Quand Paul parle trop vite, il oublie parfois une syllabe.

It uses:

• a common time clause with quand
• present tense for a habitual fact
• natural adverb placement
• everyday vocabulary

So it is a good model sentence for learners.