Je ne peux pas suivre cette conversation quand tout le monde parle trop vite.

Ne ... pas is the standard way to make a sentence negative in French.

• je peux = I can
• je ne peux pas = I cannot / I can’t

In everyday spoken French, many people drop ne and say je peux pas, but in careful speech and standard writing, ne is normally kept.

Peux is the je and tu form of the verb pouvoir in the present tense.

Present tense:

• je peux
• tu peux
• il/elle/on peut
• nous pouvons
• vous pouvez
• ils/elles peuvent

The spelling is just part of this irregular verb. The x is not pronounced separately; peux sounds like peu in speech.

After pouvoir (can / to be able to), French normally uses another verb in the infinitive.

So:

• je peux suivre = I can follow
• je ne peux pas suivre = I can’t follow

This is similar to English can + base verb.

Yes, suivre literally means to follow, but in this context it means something like:

• to keep up with
• to follow what people are saying
• to stay with the conversation

So it is not about physically following someone. It is about mentally keeping track of the discussion.

Because conversation is a feminine noun in French.

French demonstratives agree with the noun:

• ce for masculine singular
• cette for feminine singular
• ces for plural

So:

• ce livre
• cette conversation
• ces livres

Yes, la conversation would also be possible in many contexts, but cette points to a specific conversation more clearly.

• la conversation = the conversation
• cette conversation = this conversation

A learner should notice that cette often feels a bit more immediate or specific.

Because tout le monde is grammatically singular, even though it refers to many people.

So French uses a singular verb:

• tout le monde parle not
• tout le monde parlent

This is similar to how English says everyone is, not everyone are.

Tout le monde means everyone or everybody.

Literally, it looks like all the world, but in normal French it usually means everyone.

Examples:

• Tout le monde sait ça. = Everybody knows that.
• Tout le monde parle trop vite. = Everyone is speaking too fast.

French often uses the simple present where English might use the present continuous.

So:

• tout le monde parle trop vite

can naturally correspond to:

• everyone speaks too fast
• everyone is speaking too fast

French does have ways to stress an action in progress, but the simple present is very common and natural here.

This is an important difference.

• très vite = very quickly
• trop vite = too quickly / too fast

Trop shows that it is excessive, more than is comfortable or manageable. In this sentence, that idea is important: the people are speaking faster than the speaker can handle.

Both can work, but vite is much more common and natural in everyday French.

• parler vite = to speak fast
• parler rapidement = to speak rapidly

Rapidement is correct, but it sounds a bit more formal or less conversational in many situations.

Yes, quand is completely natural here. Lorsque is also possible, but it is usually a bit more formal.

• quand = when
• lorsque = when, often more formal in style

In ordinary speech, learners will hear quand much more often.

A careful pronunciation would be roughly:

Je ne peux pas suivre cette conversation quand tout le monde parle trop vite.

A few useful notes:

• je sounds like zhuh
• ne is often very light
• peux sounds like peu
• pas is pronounced pa
• suivre sounds roughly like swee-vruh
• tout le monde has a nasal sound in monde
• parle ends with a pronounced l
• trop vite links smoothly in fast speech

In casual spoken French, many speakers would say something closer to: Je peux pas suivre cette conversation... because the ne is often dropped.

Yes, absolutely. That is a very common alternative.

• Je ne peux pas suivre = I can’t follow
• Je n’arrive pas à suivre = I can’t manage to follow / I’m not able to keep up

Ne peux pas sounds a bit more direct about inability. N’arrive pas à often suggests difficulty in practice, especially because things are happening too fast.

Both are natural.