Il venditore ambulante lavora al mercatino delle pulci.

Italian often uses the definite article where English might not.

Here, il venditore ambulante means the street vendor / the traveling seller. The article il tells you we are talking about a specific person or a person presented as a definite subject in the sentence.

If you removed il, the phrase would usually sound incomplete in a normal statement like this.

Literally, it is something like seller itinerant or traveling seller.

• venditore = seller, vendor
• ambulante = itinerant, mobile, traveling, street-selling

So venditore ambulante is the normal Italian way to say street vendor, peddler, or mobile vendor, depending on context.

In Italian, adjectives often come after the noun.

So:

• venditore ambulante = vendor + itinerant/street-selling

That word order is completely natural in Italian. English usually puts adjectives before the noun, but Italian often places them after it.

Lavora is the third person singular present tense of lavorare (to work).

So:

• io lavoro = I work
• tu lavori = you work
• lui/lei lavora = he/she works

Since the subject is Il venditore ambulante (one person), Italian uses lavora.

Because Italian combines certain prepositions with definite articles.

• a + il = al

So:

• al mercatino = at the market / at the little market

This kind of contraction is very common in Italian:

• a + il = al
• a + lo = allo
• a + la = alla
• a + i = ai
• a + gli = agli
• a + le = alle

Mercatino is a diminutive form of mercato.

• mercato = market
• mercatino = little market, small market, market fair, stall market

The ending -ino often adds a sense of smallness or sometimes a more informal, charming feel.

In mercatino delle pulci, it is just the normal expression for flea market. You usually would not translate it word-for-word as little market in English.

Delle is a contraction of:

• di + le = delle

So mercatino delle pulci literally means little market of the fleas.

That sounds strange in English, but it is simply the Italian expression for flea market.

So:

• delle pulci = of the fleas
• mercatino delle pulci = flea market

Yes, it is a very common set phrase.

Italian speakers use mercatino delle pulci to mean flea market. Even though the literal wording may look odd, learners should treat it as a normal expression rather than trying to build the meaning piece by piece every time.

Yes, but in the singular it looks the same for masculine and feminine.

• masculine singular: venditore ambulante
• feminine singular: venditrice ambulante
• masculine plural: venditori ambulanti
• feminine plural: venditrici ambulanti

So ambulante is one of those adjectives ending in -e that has the same form for masculine and feminine singular.

Italian often drops subject pronouns like io, tu, lui, and lei, because the verb ending already gives useful information.

But here the subject is not a pronoun. It is a full noun phrase:

• Il venditore ambulante

That tells us exactly who is working. So the sentence needs it unless the person has already been clearly identified in the conversation.

Yes, that word order is grammatically possible, but it sounds more marked or stylistically shifted.

The most neutral order is:

• Il venditore ambulante lavora al mercatino delle pulci.

Italian is more flexible than English with word order, but changing the order often changes emphasis. Putting lavora first or moving the subject later can sound more literary, emphatic, or context-dependent.

In this sentence, lavora al mercatino delle pulci is best understood as works at the flea market.

The preposition a with places often covers several English possibilities, such as at, to, or sometimes in, depending on context. English and Italian prepositions do not always match one-to-one, so it is better to learn the whole phrase naturally:

• lavorare al mercatino delle pulci = to work at the flea market