L’agriculteur vend des légumes.

Because agriculteur begins with a vowel sound, and French usually drops the vowel of le before a vowel. This is called elision.

• le agriculteur → incorrect
• l’agriculteur → correct

So l’ here stands for le.

Yes. Agriculteur means farmer.

It is a masculine noun:

• un agriculteur = a farmer
• l’agriculteur = the farmer

The feminine form is:

• une agricultrice = a female farmer

Vend is the third-person singular form of the verb vendre, which means to sell.

The subject is l’agriculteur, which is he / the farmer, so French uses the third-person singular form:

• je vends = I sell
• tu vends = you sell
• il / elle vend = he / she sells

So:

• L’agriculteur vend = The farmer sells

Because in the present tense of vendre, the -s appears with je and tu, but not with il / elle / on.

Compare:

• je vends
• tu vends
• il vend

Since l’agriculteur is equivalent to il, the correct form is vend.

Here, des is the plural indefinite article. It usually means some or just indicates an unspecified plural noun.

So:

• des légumes = some vegetables / vegetables

In English, we often omit some, but French normally keeps the article.

In French, nouns usually need an article or determiner. You normally do not leave a plural countable noun bare the way English often does.

So French says:

• Il vend des légumes.

English can say:

• He sells vegetables.

French usually needs des here because the vegetables are being talked about in a general, indefinite way.

Because des and les do not mean the same thing.

• des légumes = some vegetables, vegetables in general, unspecified vegetables
• les légumes = the vegetables, specific vegetables already known from context

So:

• L’agriculteur vend des légumes. = The farmer sells vegetables.
• L’agriculteur vend les légumes. = The farmer sells the vegetables.

The second version sounds more specific.

Because des is plural, so the noun must also be plural.

• un légume = a vegetable
• des légumes = vegetables / some vegetables

The -s marks the plural in writing.

Normally, no. The final -s in légumes is usually silent.

So:

• légume and légumes sound very similar in isolation

The plural is mainly shown by:

• the article: des
• the written -s

A common pronunciation is roughly:

L’agriculteur vend des légumes
/la.ɡʁi.kyl.tœʁ vɑ̃ de le.ɡym/

A few helpful notes:

• L’ links directly to agriculteur
• vend sounds like vahn with a nasal vowel
• des here is pronounced day
• légumes sounds roughly like lay-güm

Also, the final d in vend is silent.

Usually, no important liaison is made in vend des here.

You would typically hear:

• vend des = vɑ̃ de

Not:

• vɑ̃z de

So this sentence is fairly straightforward to pronounce without liaison.

Yes. This sentence follows the basic Subject + Verb + Object pattern:

• L’agriculteur = subject
• vend = verb
• des légumes = object

So it matches English very closely:

• The farmer sells vegetables.

Yes, depending on context.

French present tense often covers both:

• a general action or habit: The farmer sells vegetables
• an action happening now: The farmer is selling vegetables

If you need to make right now extra clear, French can also use expressions like:

• L’agriculteur est en train de vendre des légumes.

But the simple present is very common.

Yes, but it means something slightly different.

• L’agriculteur vend des légumes. = The farmer sells vegetables.
• Un agriculteur vend des légumes. = A farmer sells vegetables.

So l’ makes it definite, while un makes it indefinite.

The é in légumes is an accent aigu. It affects pronunciation.

• é is pronounced like ay in many English approximations
• so légumes begins with a clear lay- sound

The accent is part of the spelling and should not be omitted in normal writing.

The singular is:

• un légume = a vegetable

So the singular version of the sentence would be:

• L’agriculteur vend un légume. = The farmer sells a vegetable.

That changes the meaning from plural to singular.