Il parle beaucoup quand il est nerveux.

French usually repeats the subject after words like quand when a new clause begins.

So:

• Il parle beaucoup = He talks a lot
• quand il est nerveux = when he is nervous

In English, we also repeat the subject: He talks a lot when he is nervous, not He talks a lot when is nervous.

Parle is the third person singular form of parler in the present tense, used with il and elle.

Present tense of parler:

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

Since the subject is il, the correct form is parle.

Beaucoup means a lot or much. Here it modifies the verb parle, so il parle beaucoup means he talks a lot.

French often places adverbs like this after the verb:

• Il parle beaucoup = He talks a lot
• Elle mange peu = She eats little

So even though English says talks a lot, French also uses a similar structure: parle beaucoup.

Quand is the normal word for when in sentences like this.

Examples:

• Je souris quand je suis content. = I smile when I’m happy.
• Il téléphone quand il arrive. = He calls when he arrives.

French also has lorsque, which can also mean when, but quand is more common and everyday here.

French often uses the present tense for general truths, habits, and repeated situations, just like English does.

So:

• Il parle beaucoup = He talks a lot
• quand il est nerveux = when he is nervous

This means it is something that generally happens, not just one single moment.

Here, est nerveux means is nervous. French commonly uses être + adjective to describe a state.

• il est nerveux = he is nervous
• elle est fatiguée = she is tired
• nous sommes prêts = we are ready

If you wanted to say he becomes nervous, that would be different, for example:

• Il devient nerveux.

But in your sentence, the meaning is simply that when he is in a nervous state, he talks a lot.

Adjectives in French agree with the noun or pronoun they describe in gender and number.

Here, il is masculine singular, so:

• nerveux = masculine singular

Other forms:

• nerveuse = feminine singular
• nerveux = masculine plural
• nerveuses = feminine plural

Examples:

• Il est nerveux.
• Elle est nerveuse.
• Ils sont nerveux.
• Elles sont nerveuses.

Often yes, but not always perfectly.

In this sentence, nerveux means something like:

• nervous
• tense
• anxious
• on edge

Depending on context, English might choose a slightly different word. But nervous is the most direct and natural translation here.

A simple pronunciation guide:

• Il ≈ eel
• parle ≈ parl
• beaucoup ≈ boh-KOO
• quand ≈ kahn
• il est ≈ ee-leh because of liaison
• nerveux ≈ nair-VUH

A more connected pronunciation is roughly:

eel parl boh-KOO kahn tee-leh nair-VUH

A few useful notes:

• The l in il is usually pronounced.
• The final -e in parle is silent.
• In beaucoup, the final p is silent.
• In quand, the d is usually silent.
• In nerveux, the final x is silent.

Yes, there can be.

• quand il: the d in quand is often pronounced before the vowel in il, so it can sound like kahn-til
• il est: the l links smoothly into est, so it sounds like ee-leh

So in natural speech, the middle of the sentence often flows together:

• quand il est ≈ kahn-tee-leh

This connected pronunciation is very common in spoken French.

Yes, but it means something different.

• beaucoup = a lot
• trop = too much / excessively

So:

• Il parle beaucoup quand il est nerveux. = He talks a lot when he is nervous.
• Il parle trop quand il est nerveux. = He talks too much when he is nervous.

The second version sounds more judgmental.

French does not use do/does the way English sometimes does.

English:

• He talks a lot
• Does he talk a lot?
• He does not talk a lot

French forms these differently:

• Il parle beaucoup.
• Parle-t-il beaucoup ? or Est-ce qu’il parle beaucoup ?
• Il ne parle pas beaucoup.

So the basic French sentence does not need any extra helping verb like does.

Yes. Parler can mean both, depending on context.

Examples:

• Il parle beaucoup. = He talks a lot.
• Il parle français. = He speaks French.

In your sentence, talks is the more natural English choice because the idea is that he talks a lot when nervous.

Yes, absolutely.

You can say:

• Il parle beaucoup quand il est nerveux.
• Quand il est nerveux, il parle beaucoup.

Both mean the same thing. The second version puts more emphasis on the condition when he is nervous.

Notice that in French, a comma is usually used when the sentence begins with the quand clause:

• Quand il est nerveux, il parle beaucoup.

Nerveux is an adjective. It describes the subject il after the verb être.

This is a very common pattern in French:

• Il est nerveux.
• Elle est heureuse.
• Nous sommes fatigués.

After être, adjectives describe what someone is.

You would change the subject, the verb form if needed, and the adjective agreement if needed.

Examples:

• Elle parle beaucoup quand elle est nerveuse.
  = She talks a lot when she is nervous.

• Ils parlent beaucoup quand ils sont nerveux.
  = They talk a lot when they are nervous.

• Elles parlent beaucoup quand elles sont nerveuses.
  = They talk a lot when they are nervous.
  (for an all-female group)

So both the verb and the adjective may change depending on the subject.